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Pituitary adenoma with neuronal choristoma: a report of two rare cases
Clinical Neurology and Neurosurgery 101 (1999) 128 – 132
Case report
Pituitary adenoma with neuronal choristoma: a report of two rare cases M.C. Sharma a, A.K. Karak a, A.K. Mahapatra a, C. Sarkar a,b,* a
Department of Pathology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110 029, India b Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi 110 029, India Received 28 July 1998; received in revised form 9 February 1999; accepted 9 February 1999
Abstract Two rare cases of pituitary adenoma with neuronal choristoma are described. Both patients were female and presented with features of acromegaly with elevated growth hormone and prolactin levels. Radiologically, both lesions were predominantly intrasellar in location with extension into suprasellar region, but hypothalamus was not involved. Histopathological examination revealed a mixture of chromophobe pituitary adenoma cells and neuronal cells. In both cases, the adenoma component was positive for growth hormone and prolactin. Interestingly, immunopositivity for a-subunit, cytokeratin and prolactin was seen in the adenoma and neuronal cells in one case. Our findings support the hypothesis that the neuronal cells possibly arise from adenoma cells as a result of metaplasia. © 1999 Published by Elsevier Science B.V. All rights reserved. Keywords: Pituitary adenoma; Hypothalamic hamartoma; Immunohistochemistry; Choristoma; Gangliocytic hamartoma
1. Introduction The first case of intrasellar pituitary adenoma containing neuronal or ganglionic cells was described by Kiyono in 1926 [1]. Since the first report, these lesions have been described under the headings of ganglioneuroma, ganglioneuroma and adenoma, gangliocytoma, gangliocytoma with adenoma, neurosecretory ganglion cell choristoma, neural choristoma, hypothalamic neuronal hamartoma with pituitary adenoma and hypothalamic gangliocytoma [2]. Whether this represents a composite lesion or a collision tumor has remained a curiosity for pathologists. The histologic findings are somewhat stereotypic in all the published cases, consisting of chromophobe pituitary adenoma, most often accompanied by acromegaly and neurons with or without neuropil [3]. The origin and histogenesis of the latter component remains an enigma. Considering the * Corresponding author. Tel.: + 91-11-659-3371 fax: +91-11-6862663. E-mail address: [email protected]/[email protected] (C. Sarkar)
outstanding rarity of this lesion, we describe two additional rare cases and discuss the various hypotheses postulated for development of this lesion.
2. Case 1 A 55-year-old lady presented with complaints of galactorrhoea, coarsening of facial features and enlargement of body parts, for 5 years. She attained the menopause at 45 years of age. After the menopause, she was detected to have hypertension and diabetes mellitus. Her blood pressure was 150/100 mm of Hg and fasting blood sugar was 192 mg/dl. She was investigated for acromegaly and her hormonal profile revealed growth hormone (GH) 48 ng/ml (normal 0–7 ng/ml); thyroxine (T4) 9.4 ng/ml (normal 4.5–12.5 ng/ml); thyroid stimulating hormone (TSH) 2 uU/ml (normal 0–5 uU/ml); serum cortisol 276 ng/ml (normal 50–250 ng/ ml) and prolactin (PRL) 30.0 ng/ml (normal 2.5–20 ng/ml). The response of GH to GHRH was not measured. Computerized tomography (CT) scan of the
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brain showed an enhancing sellar mass with small suprasellar extension and evidence of calcification. No infiltration of hypothalamus was seen. A diagnosis of pituitary adenoma was made and she was operated on through the transsphenoidal approach. The tumor consistency was soft and moderately vascular. Near total excision of the tumor was carried out. The arachnoid could be seen at surgery.
tions were stained with uranyl acetate and lead citrate and studied under a Philips CM-10 electron microscope. Case 1 was also referred to Professor Kalman Kovacs at the University of Toronto, Canada, for his opinion. Staining for all of the above antigens as well as for a-subunit, follicle stimulating hormone (FSH), luteinizing hormone (LH) and somatostatin was done by the kind courtesy of Professor Kovacs.
3. Case 2
5. Histologic examination
A 35-year-old female presented with complaints of headache, coarsening of facial features and enlargement of body parts for 3 years. There was no history of galactorrhoea. She was investigated with a clinical diagnosis of acromegaly. Her hormonal profile revealed T4 5.1 ng/ml (normal 4.5 – 12.5 ng/ml); serum cortisol 85 ng/ml (normal 50–250 ng/ml); GH 47.5 ng/ml (normal 0 – 7 ng/ml) and PRL 35.8 ng/ml (2.5 – 20 ng/ml). A skull X-ray showed enlarged sella. A contrast enhanced CT scan of the brain revealed an intrasellar homogeneously enhancing mass with small suprasellar extension. Sublabial transsphenoidal near total excision of the tumor was done, which was soft, necrotic and poorly vascular. It was not infiltrating the hypothalamus.
Microscopic examination of Case 1 revealed a composite lesion, consisting of areas of a small cell tumor with the appearance of a chromophobe pituitary adenoma (PAS and Orange-G negative), intermingled with numerous foci of apparently neural tissue comprising of numerous large neuron-like cells and copious quantities of neuropil (Fig. 1a). Neuron-like cells and neuropil showed strong positivity for NSE (Fig. 1b). Immunohistochemical staining revealed the strongest immunoreactivity for a-subunit in the majority of neuronal elements (including many neuronal processes) and a small minority of adenoma cells. A similar mi-
3.1. Follow-up Both patients improved clinically and their hormonal level came down after surgical resection. Post-operatively, a course of radiotherapy in a dose of 4000 rads was given, spanned over a period of 6 weeks. Both patients were doing well at last follow-up at 2 and 3 years, respectively.
4. Material and methods For light microscopy, the tumor tissue was fixed in 10% buffered formalin, routinely processed and embedded in paraffin. Five micron thick sections were stained with hematoxylin-eosin (H&E) and periodic acid schiff (PAS) stains. Immunohistochemistry was done by streptavidin biotin conjugate immunoperoxidase method using antibodies to GH (1:200 dl), PRL (1:200 dl), adrenocorticotrophic hormone (ACTH 1:250 dl), thyrotrophic hormone TSH (1:50 dl), neuron specific enolase (NSE 1:50 dl), cytokeratin (CK 1:50 dl), glial fibrillary acidic protein (GFAP, 1:100 dl) and S-100 protein (1:100 dl). (All antibodies were obtained from M/S Dakopatts, Denmark). In Case 1, tissue was also fixed in 2.5% glutaraldehyde, post fixed in 1% osmium tetroxide and processed for transmission electron microscopy. Ultrathin sec-
Fig. 1. (a,b) Photomicrographs showing a mixture of chromophobe adenoma and neuronal cells. Adenoma component is composed of sheets of small cells. Neuronal component consist of large cells with vesicular nuclei and prominent nucleoli in a fibrillary background (a: H&E × 200). Ganglion cells and fibrillary background are positive for NSE (b: × 200).
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Fig. 3. Electron micrograph showing sparsely granulated GH cell adenoma and a fibrous body (original magnification × 4200).
6. Discussion
Fig. 2. (a,b) Photomicrographs showing tumor cells positive on immunohistochemical staining for GH (a: × 200) and PRL (b: × 200). Some of the ganglion cells are also positive for PRL (arrow).
nority of adenoma cells were immunoreactive for GH and PRL (Fig. 2a,b). PRL positivity was also seen in a few neuron-like cells (Fig. 2b). Immunostaining, performed for cytokeratin, showed juxtranuclear positivity in almost every adenoma cell and many neuronal cells as well as their processes were also positive. Neurofilament protein positivity was seen in numerous neuronal processes and in some of the perikarya. GFAP positivity was observed only in a few stellate cells. Immunostainings for TSH, FSH, LH, ACTH, somatostatin and S-100 protein were negative. Electron microscopy in Case 1, revealed sparsely granulated pituitary adenoma cells (Fig. 3) and many of the cells contained fibrous bodies. Many cytoplasmic processes traversing through adenoma cells were seen. The neuronal component showed features of mature neurons with abundant cytoplasm containing rough endoplasmic reticulum (RER) and mitochondria (Fig. 4). The neurosecretory granules were sparse and small in size. Presynaptic vesicles were identified. Morphologically, Case 2 resembled Case 1 and the results of cytokeratin, GH and PRL were similar. Immunostaining for TSH and ACTH was negative. No immunostaining was performed for a-subunit, somatostatin, FSH or LH.
Neuronal tumors in the region of sella turcica are rare and their exact origin is much debated. Kiyono [1] described the first case of a pituitary adenoma with neuronal cells in an acromegalic woman in 1926. Towfighi et al. [2] reviewed the literature until 1996 and found 32 cases, including their three cases. However, the largest series, reported by Horvath et al. [3], of 14 cases was not included in their review. Female predominance and presence of acromegalic features were constant findings in both reports [2,3]. In their review, Towfighi et al. [2] found only five patients who pre-
Fig. 4. Electromicrograph of neuronal cells with numerous cell processes. Neuronal cell shows numerous mitochondria and synaptic vesicles (original magnification ×5400).
M.C. Sharma et al. / Clinical Neurology and Neurosurgery 101 (1999) 128–132
sented with Cushing’s disease, while six presented with galactorrhoea/hyperprolactinemia, of which three had associated acromegaly. Both the patients in our study were female presenting with acromegaly and Case 1, in addition, had galactorrhoea. Serum levels of GH and PRL were, however, high in both cases. Morphologic findings are stereotypic in all reported cases, consisting of chromophobe pituitary adenoma and neurons with or without neuropil. The proportion of the two components varies considerably in individual cases. Some tumors contain more of the adenoma component, while others have more of the ganglionic/ neuronal component. The ganglion cells have abundant cytoplasm with Nissl substance resembling hypothalamic neurons [4–7]. Both the cases under discussion had adenoma and neuronal components which contained Nissl substance. Horvath et al. [3] in 1994, described intermediate cells showing features of both adenoma and neuronal cells. In the present report, we also observed similar findings in one case. In a review of literature, Towfighi et al. [2] found immunoreactivity to GH in 18 of 23 cases. Of 18 cases with GH positivity, ten also showed PRL positivity, thereby suggesting a mixed GH-PRL tumor. Isolated PRL positivity was observed only in two cases. ACTH positivity was seen in six of 21 cases, of which two were also positive for GH and one for PRL, suggesting the plurihormonal nature of these tumors. In the series of Horvath et al. [3], GH positivity was seen in all cases (including three cases which were clinically silent). PRL positivity was observed in 13 of 15 tumors, however, significant positivity was present only in one case of mixed GH-PRL adenoma. In contrast, positivity to GH and PRL was observed in both the cases under discussion and interestingly in one case, PRL positivity was also observed in the neuronal cells, as has been reported by Li et al. [4] in two of their cases. Earlier, ACTH positivity in the ganglion cells has been reported [2,4]. Further, positivity for low molecular weight CK and a-subunit was observed not only in the adenoma component but also in some of the neurons and their processes in Case 1. The exact histogenesis of these composite lesions is of much debate. Kiyono [1] interpreted these neuronal cells as choristoma. Later on, many authors hypothesised that proliferation of these heterotopic intrasellar hypothalamic-like neurons gives rise to gangliocytoma, which through their secretions induce the adenomatous proliferation of pituitary cells [7,9]. This theory was further supported by positivity of these neurons to many of the hypothalamic releasing hormones [7–10]. This hypothesis, however, does not explain why local production of growth hormone releasing hormone (GHRH) leads to adenoma formation rather than the expected hyperplasia. Secondly, there is lack of correlation between the type of adenoma and the type of
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releasing hormone in the ganglion or neuron-like cells [2,4]. The second hypothesis proposes that both the neuronal and adenoma components originate from embryonal rests that may contain cells showing features intermediate between adenoma and hypophyseal cells. These intermediate cells have been noted in pituitary gangliocytomas, since adenohypophysis and infundibular regions have close embryonic origin [11]. The adenohypophyseal hormones and neuronal markers, such as synaptophysin and neuron specific enolase have been demonstrated in the infundibular neurons [12–16]. The third hypothesis postulates that these neuronlike cells arise from the sparsely granulated adenomas as a result of metaplasia [3]. Immunohistochemical stains and electron microscopic studies have demonstrated intermediate cells between neurons and adenohypophyseal cells. This observation has been further supported, not only by the demonstration of neuronal processes on ultrastructural examination of sparsely granulated GH cell adenomas [3], but also by experimental animal studies. Martinez-Campos and Dannies [17] had demonstrated spontaneous transformation of cultured rat adenohypophyseal cells into cells with neuronal processes. The emergence of neural tissue was observed by Schechter et al. [18] within anterior pituitary tumors of mice carrying a hybrid transgene containing the 5%-flanking region of the human glycoprotein hormone a-subunit gene and the coding region of the SV 40 T antigen. Therefore, this composite lesion may represent lineage infidelity in an endocrine tissue as both epithelial and neural features have also been demonstrated in rat PC 12 pheochromocytoma cell lines [19], human carcinoid tumor [20] and medullary carcinoma of the thyroid [21]. The immunopositivity for a-subunit, CK and PRL in both adenoma cells and neurons in the two cases in our series adds support to this hypothesis. Lastly, the possibility that this lesion represents a collision tumor of pituitary adenoma and a gangliocytoma, is not considered. Radiologically, both these lesions were predominantly intrasellar with small suprasellar extension. According to Hardy and Verzina’s [22] classification of pituitary tumor, they are placed in the categories of macroadenoma, grade IV. However, radiologically as well as surgically, these lesions were not reaching or infiltrating the hypothalamic region.
Acknowledgements The authors wish to thank Professor Kalman Kovacs, Department of Pathology, St. Michael’s Hospital, Toronto, Ont., Canada for consultation, immunostaining and all the help rendered. The authors also wish to
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thank Mr Rajeshwar Khadia for his technical assistance and Mr Kamal for his secretarial assistance.
References [1] Kiyono H. Die histopathologie der hypophyse. Virchows Arch A Pathol Anat Histopathol 1926;259:388–465. [2] Towfighi J, Salam MM, McLendon RE, Powers S, Page RB. Ganglion cell-containing tumors of the pituitary gland. Arch Path Lab Med 1996;120:369–77. [3] Horvath E, Kovacs K, Scheithauer BW, Lloyd RV, Smyth HS. Pituitary adenoma with neuronal choristoma (PANCH): Composite lesion or lineage infidelity? Ultrastruct Pathol 1994;18:565 – 74. [4] Li JY, Racadot O, Kujas M, Koudari M, Peillon F, Racadot J. Immunohistochemistry of four mixed pituitary adenomas and intrasellar gangliocytomas associated with different clinical syndromes: acromegaly, amenorrhoea-galactorrhoea, Cushing’s disease and isolated tumoral syndrome. Acta Neuropathol (Berl) 1989;77:320 – 8. [5] Muller W. Uber das gemeinsame vorkommen eines hypophysenadenoms mit einem gangliocytom in zwei fallen. Ein beitrag zur frage der neurosekretion. Acta Neuro Chir (Wien) 1959;7:13 – 29. [6] Rhodes RH, Dusseau JJ, Boyd AS, Knigge KM. Intrasellar neural-adenohypophyseal choristoma: a morphological immunohistochemical study. J Neuropathol Exp Neurol 1982;41:267 – 80. [7] Asa SL, Scheithauer BW, Bilbao JM, Horvath E, Ryan N, Randall RV, Laws ER, Singer W, Linfooot JA, Thorner MO, Vale W. A case of hypothalamic acromegaly: A clinicopathology study of six patients with hypothalamic gangliocytomas producing growth hormone releasing factor. J Clin Endocrinol Metabol 1984;58:796 – 803. [8] Saeger W, Puchner MJA, Ludecke DK. Combined sellar gangliocytoma and pituitary adenoma in acromegaly or Cushing’s disease: a report of 3 cases. Virch Arch A Pathol Anat Histopathol 1994;425:93 –9. [9] Puchner MJA, Ludecke DK, Valdueza JM, et al. Cushing’s disease in a child caused by a corticotropin-releasing hormone secreting intrasellar gangliocytoma associated with an adenocorticotropic hormone secreting pituitary adenoma. Neurosurgery 1993;33:920 – 5.
.
[10] Asa SL, Bilbao JM, Kovacs K, Linfoot JA. Hypothalamic neuronal hamartoma associated with pituitary growth hormone cell adenoma and acromegaly. Acta Neuropathol (Berl) 1980;52:231 – 4. [11] Takor TT, Pearse AGE. Neuroectodermal origin of avian hypothalamo-hypophyseal complex: the role of the ventral neural ridge. J Embryol Exp Morph 1975;34:311 – 25. [12] Bugnon C, Bloch B, Lenys D, Fellmann D. Infundibular neurons of human hypothalamus simultaneously reactive with antisera against endorphins, ACTH, MSH and B-LPH. Cell Tissue Res 1979;199:177 – 96. [13] Ishikawa K, Katakai K, Tanaka S, Haga S, Mochida H, Itol K. Pro-opiomelanocortin-containing neurons in rat median eminence. Neuroendocrinology 1992;56:178 – 84. [14] Lechan RM, King JC, Molitch ME, Aalberg J. Immunohistochemical localisation of human growth hormone-like material in the median eminence of the rat: light and electron microscopic observations. Neurosci Lett 1982;30:229 – 34. [15] Holm R, Nesland JM, Attramadal A, Halse J, Johannessen JV. Null cell adenomas of the pituitary gland: an immunohistochemical study. J Pathol 1989;158:213 – 7. [16] Stefaneanu L, Ryan N, Kovacs K. Immunohistochemical localisation of synaptophysin in human hypophyses and pituitary adenomas. Arch Pathol Lab Med 1989;112:801 – 4. [17] Martinez-Campos A, Dannies PS. A possible differentiation of anterior pituitary cells in collagen gel into neurons. Cell Tissue Res 1986;244:21 – 6. [18] Schechter J, Windle JJ, Stauber C, Mellon PL. Neural tissue within anterior pituitary tumors generated by oncogene expression in transgenic mice. Neuroendocrinology 1992;56:300–11. [19] Franke WW, Grund C, Achstatter T. Co-expression of cytokeratins and neurofilament proteins in a permanent cell line: cultured rat PC 12 cells combine neuronal and epithelial features. J Cell Biol 1986;103:1933– 43. [20] Ahlman H, Wigander AL, Nilsson O, et al. Presence of nerve growth factor like immunoreactivity in carcinoid tumor cells and indication of a neuronal phenotype in long term culture. Int J Cancer 1989;43:949 – 55. [21] Tamir H, Liu KP, Payette RF, et al. Human medullary thyroid carcinoma: characterisation of the serotonergic and neuronal properties of a neuroendodermally derived cell line. J Neurosci 1989;9:499 – 521. [22] Hardy J, Verzina JL. Transsphenoidal microsurgery of intracranial neoplasms. In: Thompson RA, Green JR, editors. Advances in neurology. New York: Raven Press, 1976:261 – 74.
Case report
Pituitary adenoma with neuronal choristoma: a report of two rare cases M.C. Sharma a, A.K. Karak a, A.K. Mahapatra a, C. Sarkar a,b,* a
Department of Pathology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110 029, India b Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi 110 029, India Received 28 July 1998; received in revised form 9 February 1999; accepted 9 February 1999
Abstract Two rare cases of pituitary adenoma with neuronal choristoma are described. Both patients were female and presented with features of acromegaly with elevated growth hormone and prolactin levels. Radiologically, both lesions were predominantly intrasellar in location with extension into suprasellar region, but hypothalamus was not involved. Histopathological examination revealed a mixture of chromophobe pituitary adenoma cells and neuronal cells. In both cases, the adenoma component was positive for growth hormone and prolactin. Interestingly, immunopositivity for a-subunit, cytokeratin and prolactin was seen in the adenoma and neuronal cells in one case. Our findings support the hypothesis that the neuronal cells possibly arise from adenoma cells as a result of metaplasia. © 1999 Published by Elsevier Science B.V. All rights reserved. Keywords: Pituitary adenoma; Hypothalamic hamartoma; Immunohistochemistry; Choristoma; Gangliocytic hamartoma
1. Introduction The first case of intrasellar pituitary adenoma containing neuronal or ganglionic cells was described by Kiyono in 1926 [1]. Since the first report, these lesions have been described under the headings of ganglioneuroma, ganglioneuroma and adenoma, gangliocytoma, gangliocytoma with adenoma, neurosecretory ganglion cell choristoma, neural choristoma, hypothalamic neuronal hamartoma with pituitary adenoma and hypothalamic gangliocytoma [2]. Whether this represents a composite lesion or a collision tumor has remained a curiosity for pathologists. The histologic findings are somewhat stereotypic in all the published cases, consisting of chromophobe pituitary adenoma, most often accompanied by acromegaly and neurons with or without neuropil [3]. The origin and histogenesis of the latter component remains an enigma. Considering the * Corresponding author. Tel.: + 91-11-659-3371 fax: +91-11-6862663. E-mail address: [email protected]/[email protected] (C. Sarkar)
outstanding rarity of this lesion, we describe two additional rare cases and discuss the various hypotheses postulated for development of this lesion.
2. Case 1 A 55-year-old lady presented with complaints of galactorrhoea, coarsening of facial features and enlargement of body parts, for 5 years. She attained the menopause at 45 years of age. After the menopause, she was detected to have hypertension and diabetes mellitus. Her blood pressure was 150/100 mm of Hg and fasting blood sugar was 192 mg/dl. She was investigated for acromegaly and her hormonal profile revealed growth hormone (GH) 48 ng/ml (normal 0–7 ng/ml); thyroxine (T4) 9.4 ng/ml (normal 4.5–12.5 ng/ml); thyroid stimulating hormone (TSH) 2 uU/ml (normal 0–5 uU/ml); serum cortisol 276 ng/ml (normal 50–250 ng/ ml) and prolactin (PRL) 30.0 ng/ml (normal 2.5–20 ng/ml). The response of GH to GHRH was not measured. Computerized tomography (CT) scan of the
0303-8467/99/$ - see front matter © 1999 Published by Elsevier Science B.V. All rights reserved. PII: S 0 3 0 3 - 8 4 6 7 ( 9 9 ) 0 0 0 1 8 - 9
M.C. Sharma et al. / Clinical Neurology and Neurosurgery 101 (1999) 128–132
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brain showed an enhancing sellar mass with small suprasellar extension and evidence of calcification. No infiltration of hypothalamus was seen. A diagnosis of pituitary adenoma was made and she was operated on through the transsphenoidal approach. The tumor consistency was soft and moderately vascular. Near total excision of the tumor was carried out. The arachnoid could be seen at surgery.
tions were stained with uranyl acetate and lead citrate and studied under a Philips CM-10 electron microscope. Case 1 was also referred to Professor Kalman Kovacs at the University of Toronto, Canada, for his opinion. Staining for all of the above antigens as well as for a-subunit, follicle stimulating hormone (FSH), luteinizing hormone (LH) and somatostatin was done by the kind courtesy of Professor Kovacs.
3. Case 2
5. Histologic examination
A 35-year-old female presented with complaints of headache, coarsening of facial features and enlargement of body parts for 3 years. There was no history of galactorrhoea. She was investigated with a clinical diagnosis of acromegaly. Her hormonal profile revealed T4 5.1 ng/ml (normal 4.5 – 12.5 ng/ml); serum cortisol 85 ng/ml (normal 50–250 ng/ml); GH 47.5 ng/ml (normal 0 – 7 ng/ml) and PRL 35.8 ng/ml (2.5 – 20 ng/ml). A skull X-ray showed enlarged sella. A contrast enhanced CT scan of the brain revealed an intrasellar homogeneously enhancing mass with small suprasellar extension. Sublabial transsphenoidal near total excision of the tumor was done, which was soft, necrotic and poorly vascular. It was not infiltrating the hypothalamus.
Microscopic examination of Case 1 revealed a composite lesion, consisting of areas of a small cell tumor with the appearance of a chromophobe pituitary adenoma (PAS and Orange-G negative), intermingled with numerous foci of apparently neural tissue comprising of numerous large neuron-like cells and copious quantities of neuropil (Fig. 1a). Neuron-like cells and neuropil showed strong positivity for NSE (Fig. 1b). Immunohistochemical staining revealed the strongest immunoreactivity for a-subunit in the majority of neuronal elements (including many neuronal processes) and a small minority of adenoma cells. A similar mi-
3.1. Follow-up Both patients improved clinically and their hormonal level came down after surgical resection. Post-operatively, a course of radiotherapy in a dose of 4000 rads was given, spanned over a period of 6 weeks. Both patients were doing well at last follow-up at 2 and 3 years, respectively.
4. Material and methods For light microscopy, the tumor tissue was fixed in 10% buffered formalin, routinely processed and embedded in paraffin. Five micron thick sections were stained with hematoxylin-eosin (H&E) and periodic acid schiff (PAS) stains. Immunohistochemistry was done by streptavidin biotin conjugate immunoperoxidase method using antibodies to GH (1:200 dl), PRL (1:200 dl), adrenocorticotrophic hormone (ACTH 1:250 dl), thyrotrophic hormone TSH (1:50 dl), neuron specific enolase (NSE 1:50 dl), cytokeratin (CK 1:50 dl), glial fibrillary acidic protein (GFAP, 1:100 dl) and S-100 protein (1:100 dl). (All antibodies were obtained from M/S Dakopatts, Denmark). In Case 1, tissue was also fixed in 2.5% glutaraldehyde, post fixed in 1% osmium tetroxide and processed for transmission electron microscopy. Ultrathin sec-
Fig. 1. (a,b) Photomicrographs showing a mixture of chromophobe adenoma and neuronal cells. Adenoma component is composed of sheets of small cells. Neuronal component consist of large cells with vesicular nuclei and prominent nucleoli in a fibrillary background (a: H&E × 200). Ganglion cells and fibrillary background are positive for NSE (b: × 200).
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Fig. 3. Electron micrograph showing sparsely granulated GH cell adenoma and a fibrous body (original magnification × 4200).
6. Discussion
Fig. 2. (a,b) Photomicrographs showing tumor cells positive on immunohistochemical staining for GH (a: × 200) and PRL (b: × 200). Some of the ganglion cells are also positive for PRL (arrow).
nority of adenoma cells were immunoreactive for GH and PRL (Fig. 2a,b). PRL positivity was also seen in a few neuron-like cells (Fig. 2b). Immunostaining, performed for cytokeratin, showed juxtranuclear positivity in almost every adenoma cell and many neuronal cells as well as their processes were also positive. Neurofilament protein positivity was seen in numerous neuronal processes and in some of the perikarya. GFAP positivity was observed only in a few stellate cells. Immunostainings for TSH, FSH, LH, ACTH, somatostatin and S-100 protein were negative. Electron microscopy in Case 1, revealed sparsely granulated pituitary adenoma cells (Fig. 3) and many of the cells contained fibrous bodies. Many cytoplasmic processes traversing through adenoma cells were seen. The neuronal component showed features of mature neurons with abundant cytoplasm containing rough endoplasmic reticulum (RER) and mitochondria (Fig. 4). The neurosecretory granules were sparse and small in size. Presynaptic vesicles were identified. Morphologically, Case 2 resembled Case 1 and the results of cytokeratin, GH and PRL were similar. Immunostaining for TSH and ACTH was negative. No immunostaining was performed for a-subunit, somatostatin, FSH or LH.
Neuronal tumors in the region of sella turcica are rare and their exact origin is much debated. Kiyono [1] described the first case of a pituitary adenoma with neuronal cells in an acromegalic woman in 1926. Towfighi et al. [2] reviewed the literature until 1996 and found 32 cases, including their three cases. However, the largest series, reported by Horvath et al. [3], of 14 cases was not included in their review. Female predominance and presence of acromegalic features were constant findings in both reports [2,3]. In their review, Towfighi et al. [2] found only five patients who pre-
Fig. 4. Electromicrograph of neuronal cells with numerous cell processes. Neuronal cell shows numerous mitochondria and synaptic vesicles (original magnification ×5400).
M.C. Sharma et al. / Clinical Neurology and Neurosurgery 101 (1999) 128–132
sented with Cushing’s disease, while six presented with galactorrhoea/hyperprolactinemia, of which three had associated acromegaly. Both the patients in our study were female presenting with acromegaly and Case 1, in addition, had galactorrhoea. Serum levels of GH and PRL were, however, high in both cases. Morphologic findings are stereotypic in all reported cases, consisting of chromophobe pituitary adenoma and neurons with or without neuropil. The proportion of the two components varies considerably in individual cases. Some tumors contain more of the adenoma component, while others have more of the ganglionic/ neuronal component. The ganglion cells have abundant cytoplasm with Nissl substance resembling hypothalamic neurons [4–7]. Both the cases under discussion had adenoma and neuronal components which contained Nissl substance. Horvath et al. [3] in 1994, described intermediate cells showing features of both adenoma and neuronal cells. In the present report, we also observed similar findings in one case. In a review of literature, Towfighi et al. [2] found immunoreactivity to GH in 18 of 23 cases. Of 18 cases with GH positivity, ten also showed PRL positivity, thereby suggesting a mixed GH-PRL tumor. Isolated PRL positivity was observed only in two cases. ACTH positivity was seen in six of 21 cases, of which two were also positive for GH and one for PRL, suggesting the plurihormonal nature of these tumors. In the series of Horvath et al. [3], GH positivity was seen in all cases (including three cases which were clinically silent). PRL positivity was observed in 13 of 15 tumors, however, significant positivity was present only in one case of mixed GH-PRL adenoma. In contrast, positivity to GH and PRL was observed in both the cases under discussion and interestingly in one case, PRL positivity was also observed in the neuronal cells, as has been reported by Li et al. [4] in two of their cases. Earlier, ACTH positivity in the ganglion cells has been reported [2,4]. Further, positivity for low molecular weight CK and a-subunit was observed not only in the adenoma component but also in some of the neurons and their processes in Case 1. The exact histogenesis of these composite lesions is of much debate. Kiyono [1] interpreted these neuronal cells as choristoma. Later on, many authors hypothesised that proliferation of these heterotopic intrasellar hypothalamic-like neurons gives rise to gangliocytoma, which through their secretions induce the adenomatous proliferation of pituitary cells [7,9]. This theory was further supported by positivity of these neurons to many of the hypothalamic releasing hormones [7–10]. This hypothesis, however, does not explain why local production of growth hormone releasing hormone (GHRH) leads to adenoma formation rather than the expected hyperplasia. Secondly, there is lack of correlation between the type of adenoma and the type of
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releasing hormone in the ganglion or neuron-like cells [2,4]. The second hypothesis proposes that both the neuronal and adenoma components originate from embryonal rests that may contain cells showing features intermediate between adenoma and hypophyseal cells. These intermediate cells have been noted in pituitary gangliocytomas, since adenohypophysis and infundibular regions have close embryonic origin [11]. The adenohypophyseal hormones and neuronal markers, such as synaptophysin and neuron specific enolase have been demonstrated in the infundibular neurons [12–16]. The third hypothesis postulates that these neuronlike cells arise from the sparsely granulated adenomas as a result of metaplasia [3]. Immunohistochemical stains and electron microscopic studies have demonstrated intermediate cells between neurons and adenohypophyseal cells. This observation has been further supported, not only by the demonstration of neuronal processes on ultrastructural examination of sparsely granulated GH cell adenomas [3], but also by experimental animal studies. Martinez-Campos and Dannies [17] had demonstrated spontaneous transformation of cultured rat adenohypophyseal cells into cells with neuronal processes. The emergence of neural tissue was observed by Schechter et al. [18] within anterior pituitary tumors of mice carrying a hybrid transgene containing the 5%-flanking region of the human glycoprotein hormone a-subunit gene and the coding region of the SV 40 T antigen. Therefore, this composite lesion may represent lineage infidelity in an endocrine tissue as both epithelial and neural features have also been demonstrated in rat PC 12 pheochromocytoma cell lines [19], human carcinoid tumor [20] and medullary carcinoma of the thyroid [21]. The immunopositivity for a-subunit, CK and PRL in both adenoma cells and neurons in the two cases in our series adds support to this hypothesis. Lastly, the possibility that this lesion represents a collision tumor of pituitary adenoma and a gangliocytoma, is not considered. Radiologically, both these lesions were predominantly intrasellar with small suprasellar extension. According to Hardy and Verzina’s [22] classification of pituitary tumor, they are placed in the categories of macroadenoma, grade IV. However, radiologically as well as surgically, these lesions were not reaching or infiltrating the hypothalamic region.
Acknowledgements The authors wish to thank Professor Kalman Kovacs, Department of Pathology, St. Michael’s Hospital, Toronto, Ont., Canada for consultation, immunostaining and all the help rendered. The authors also wish to
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thank Mr Rajeshwar Khadia for his technical assistance and Mr Kamal for his secretarial assistance.
References [1] Kiyono H. Die histopathologie der hypophyse. Virchows Arch A Pathol Anat Histopathol 1926;259:388–465. [2] Towfighi J, Salam MM, McLendon RE, Powers S, Page RB. Ganglion cell-containing tumors of the pituitary gland. Arch Path Lab Med 1996;120:369–77. [3] Horvath E, Kovacs K, Scheithauer BW, Lloyd RV, Smyth HS. Pituitary adenoma with neuronal choristoma (PANCH): Composite lesion or lineage infidelity? Ultrastruct Pathol 1994;18:565 – 74. [4] Li JY, Racadot O, Kujas M, Koudari M, Peillon F, Racadot J. Immunohistochemistry of four mixed pituitary adenomas and intrasellar gangliocytomas associated with different clinical syndromes: acromegaly, amenorrhoea-galactorrhoea, Cushing’s disease and isolated tumoral syndrome. Acta Neuropathol (Berl) 1989;77:320 – 8. [5] Muller W. Uber das gemeinsame vorkommen eines hypophysenadenoms mit einem gangliocytom in zwei fallen. Ein beitrag zur frage der neurosekretion. Acta Neuro Chir (Wien) 1959;7:13 – 29. [6] Rhodes RH, Dusseau JJ, Boyd AS, Knigge KM. Intrasellar neural-adenohypophyseal choristoma: a morphological immunohistochemical study. J Neuropathol Exp Neurol 1982;41:267 – 80. [7] Asa SL, Scheithauer BW, Bilbao JM, Horvath E, Ryan N, Randall RV, Laws ER, Singer W, Linfooot JA, Thorner MO, Vale W. A case of hypothalamic acromegaly: A clinicopathology study of six patients with hypothalamic gangliocytomas producing growth hormone releasing factor. J Clin Endocrinol Metabol 1984;58:796 – 803. [8] Saeger W, Puchner MJA, Ludecke DK. Combined sellar gangliocytoma and pituitary adenoma in acromegaly or Cushing’s disease: a report of 3 cases. Virch Arch A Pathol Anat Histopathol 1994;425:93 –9. [9] Puchner MJA, Ludecke DK, Valdueza JM, et al. Cushing’s disease in a child caused by a corticotropin-releasing hormone secreting intrasellar gangliocytoma associated with an adenocorticotropic hormone secreting pituitary adenoma. Neurosurgery 1993;33:920 – 5.
.
[10] Asa SL, Bilbao JM, Kovacs K, Linfoot JA. Hypothalamic neuronal hamartoma associated with pituitary growth hormone cell adenoma and acromegaly. Acta Neuropathol (Berl) 1980;52:231 – 4. [11] Takor TT, Pearse AGE. Neuroectodermal origin of avian hypothalamo-hypophyseal complex: the role of the ventral neural ridge. J Embryol Exp Morph 1975;34:311 – 25. [12] Bugnon C, Bloch B, Lenys D, Fellmann D. Infundibular neurons of human hypothalamus simultaneously reactive with antisera against endorphins, ACTH, MSH and B-LPH. Cell Tissue Res 1979;199:177 – 96. [13] Ishikawa K, Katakai K, Tanaka S, Haga S, Mochida H, Itol K. Pro-opiomelanocortin-containing neurons in rat median eminence. Neuroendocrinology 1992;56:178 – 84. [14] Lechan RM, King JC, Molitch ME, Aalberg J. Immunohistochemical localisation of human growth hormone-like material in the median eminence of the rat: light and electron microscopic observations. Neurosci Lett 1982;30:229 – 34. [15] Holm R, Nesland JM, Attramadal A, Halse J, Johannessen JV. Null cell adenomas of the pituitary gland: an immunohistochemical study. J Pathol 1989;158:213 – 7. [16] Stefaneanu L, Ryan N, Kovacs K. Immunohistochemical localisation of synaptophysin in human hypophyses and pituitary adenomas. Arch Pathol Lab Med 1989;112:801 – 4. [17] Martinez-Campos A, Dannies PS. A possible differentiation of anterior pituitary cells in collagen gel into neurons. Cell Tissue Res 1986;244:21 – 6. [18] Schechter J, Windle JJ, Stauber C, Mellon PL. Neural tissue within anterior pituitary tumors generated by oncogene expression in transgenic mice. Neuroendocrinology 1992;56:300–11. [19] Franke WW, Grund C, Achstatter T. Co-expression of cytokeratins and neurofilament proteins in a permanent cell line: cultured rat PC 12 cells combine neuronal and epithelial features. J Cell Biol 1986;103:1933– 43. [20] Ahlman H, Wigander AL, Nilsson O, et al. Presence of nerve growth factor like immunoreactivity in carcinoid tumor cells and indication of a neuronal phenotype in long term culture. Int J Cancer 1989;43:949 – 55. [21] Tamir H, Liu KP, Payette RF, et al. Human medullary thyroid carcinoma: characterisation of the serotonergic and neuronal properties of a neuroendodermally derived cell line. J Neurosci 1989;9:499 – 521. [22] Hardy J, Verzina JL. Transsphenoidal microsurgery of intracranial neoplasms. In: Thompson RA, Green JR, editors. Advances in neurology. New York: Raven Press, 1976:261 – 74.