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Ancient Schwannoma Arising in a Lymph Node
PATHOLOGY
Teaching Case
RESEARCH AND PRACTICE © Urban & Fischer Verlag http://www.urbanfischer.de/journals/prp
Ancient Schwannoma Arising in a Lymph Node: Report of a Case and Review of the Literature S. Piana, M. C. Gelli, A. Cavazza, L. Serra, G. Gardini Servizio di Anatomia ed Istologia Patologica, Ospedale Santa Maria Nuova, Reggio Emilia, Italy
Summary
Clinical History
We report a case of an intranodal schwannoma in a 79year-old woman. The patient underwent a left colectomy for a colonic adenocarcinoma, with regional lymph node dissection. Macroscopic examination of the specimen revealed a well-circumscribed 4 cm nodule located in the pericolic fat. Macroscopically, it was interpreted as a metastatic lymph node. Microscopically, the nodule was composed of a proliferation of bland spindle cells, was immunohistochemically positive for S100 protein, and negative for smooth muscle actin, desmin, and cytokeratin. The pathological findings led to the diagnosis of a very rare case of primary schwannoma of the lymph node.
A 79-year-old woman with an unremarkable medical history presented with abdominal pain, distension and stipsi, and with heme-positive stools. A left colonic neoplasm was diagnosed by colonscopy, and a conventional adenocarcinoma was confirmed by histological examination of the endoscopic biopsies. Routine preoperative examination revealed neither metastatic localizations nor associated diseases. The patient underwent a left colectomy with regional lymph node dissection. The postoperative course was uneventful.
Results Key words: Schwannoma – Neurilemmoma – Lymph node – Palisaded myofibroblastoma – Immunohistochemistry
Introduction Schwannomas arising in lymph nodes are extremely rare [3, 9]. Some cases previously diagnosed as intranodal schwannomas have been reclassified as palisaded myofibroblastomas on the basis of some peculiar histological and immunohistochemical features [10]. Their importance mainly lies in the differentiation between a metastatic neoplasm and a primary tumor. In this case, the lesion was macroscopically interpreted as a lymph node metastasis of colonic adenocarcinoma. We report a case of an ancient schwannoma arising in an abdominal lymph node, and briefly review the literature on intranodal spindle cell neoplasms. Pathol. Res. Pract. 198: 51–54 (2002)
Gross examination of the colectomy specimen revealed an ulcerated neoplasm, 5 cm in greatest diameter, which was deeply invasive on cut sections. Eight lymph nodes were found in the adjacent pericolic fat. The largest node measured 4 × 3 × 3 cm, was well circumscribed, and was surrounded by a thin rim of fibrous capsule. The cut surfaces were yellowish with focal, microcystic areas. Microscopically the neoplasm was interpreted as an adenocarcinoma NOS, T3NO. All the lymph nodes were free of tumor invasion. The largest pericolic nodule was identified as a lymph node because of the presence of a
Address for correspondence: Simonetta Piana, Servizio di Anatomia ed Istologia Patologica, Ospedale Santa Maria Nuova, Viale Risorgimento 80, 42100 Reggio Emilia, Italy. Tel.: +39-522-295919, Fax: +39-522-296945. E-mail: [email protected] 0344-0338/02/198/1-51 $15.00/0
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Ancient Schwannoma Arising in a Lymph Node · 53
Fig. 5. The spindle cells are strongly immunoreactive to S100 protein (A) and negative to smooth muscle actin (B). Internal positive controls are apparent.
peripheral rim of compressed lymphoid tissue arranged in follicles, with many subcapsular sinuses and high endothelial venules; its center was occupied by proliferating spindle cells (Fig. 1), with twisted nuclei and ill-defined cytoplasmic borders (Fig. 2). The spindle cells were mainly arranged in compact interlacing bundles, with focal palisading, reminiscent of Antoni A growth pattern, alternating with the loose texture of Antoni B pattern. Focally hyperchromatic, atypical nuclei were noted (Fig. 3), but neither necrotic areas nor mitoses were present. Degenerative changes were apparent, including microcyst formation, xanthomatous infiltration, and perivascular hyalinization (Fig. 4). Immunohistochemically, there was strong and diffuse staining of the spindle cells with antibody to S100 protein (Fig. 5A) and vimentin, with no antibody reactivity to smooth muscle actin (Fig. 5B) , desmin, CD34, and cytokeratin.
Discussion Primary non-lymphoid neoplasms of lymph nodes are quite uncommon. Among them, the occurrence of spindle cell neoplasms is often based only on “anecdote” and not fact. Their importance lies in the differentiation between metastasis from carcinomas or melanomas and a lymphadenopathic form of Kaposi’s sarcoma. Most spindle cell intranodal lesions are represented by the hemorrhagic spindle cell tumor with amianthoid fibers, also referred to as palisaded myofibroblastoma [6, 10]. The latter was first described in 1989, and was then reported occurring at many anatomical sites [1, 2, 4, 5, 7]. One of the largest series, including many lesions initially defined as intranodal schwannoma, was subsequently reviewed by Weiss et al. [10]. Palisaded myofibroblastoma is always characterized by stellate areas of collagen deposition, also called
Fig. 1. The lymph node is almost completely involved by solidly proliferating spindle cells; the capsule is unremarkable. Hematoxylin-eosin, × 20. Fig. 2. A peripheral rim of compressed lymphoid tissue is associated with a central proliferation of spindle cells with nuclear atypia. Hematoxylin-eosin, ×100. Fig. 3. Spindle cells with oval, hyperchromatic nuclei, haphazardly arranged. Hematoxylin-eosin, × 100. Fig. 4. Hyalinized vessels and pseudocystic degeneration. Hematoxylin-eosin, × 200.
54 · S. Piana et al.
“amianthoid fibers”, which are lacking in our case; strong immunohistochemical reactivity to smooth muscle actin and negativity to S100 protein confirm the myofibroblastic differentiation of the proliferating cells. Lymphadenopathic Kaposi’s sarcoma is a highly cellular lesion composed of fascicles of spindle cells intermingled with slits containing extravasated erythrocytes. The immunohistochemical profile, reminiscent of endothelial differentiation, the interspersed erythrocytes, and the typical eosinophilic hyaline globules allow for the correct diagnosis [9]. Several uncommon proliferative lesions originating from smooth muscle cells can occur in lymph nodes [8, 9]. They are occasionally found and mainly include leiomyoma, angiomyolipoma, leiomyomatosis, and lymphangioleiomyomatosis. Immunohistochemical features, along with the clinical setting, are helpful in rendering the correct diagnosis. Schwannomas arising in lymph node are very rare and have been reported only briefly [3] or just mentioned [5]. They typically show a proliferation of compact bundles of bland-looking spindle cells, sometimes exhibiting a whorled pattern and alternating with less cellular Antoni B areas. Immunohistochemically, S100 protein is easily demonstrated, while there is no evidence of smooth muscle or epithelial differentiation. In this case, all the hallmarks of schwannomas were present, along with some peculiar features, i.e., extensive hyalinization with cystic degeneration, and scattered spindle cells with hyperchromatic and tapered nuclei. These changes have been referred to as “ancient” features in schwannomas and do not imply any malignant transformation; nor do they have prognostic value. Differential diagnostically, one might also consider a nodal localization of a malignant peripheral nerve sheath tumor (MPNST) or a spindle cell melanoma. First, the clinical history and the clinical examination of the patient ruled out other neoplasms apart from colonic adenocarcinoma; second, MPNSTs and spindle cell melanomas can then be recognized on histological grounds alone because of their marked cellularity, mitotic activity, and cytological pleomorphism. Such a pleomorphism clearly resembles a sarcoma and differs from the degenerative changes of ancient schwannomas. In conclusion, we have reported a case of primary ancient schwannoma arising in a lymph node and macroscopically interpreted as a metastasis. Intranodal
schwannomas can therefore reproduce all the morphological features of schwannomas arising at extranodal sites and must be considered when it comes to diagnosing an intranodal spindle cell neoplasm.
References 1. Barbareschi M, Mariscotti C, Ferrero S, Pignatiello U (1990) Intranodal hemorrhagic spindle cell tumor: a benign Kaposi-like nodal tumor. Histopathology 17: 93–96 2. Fletcher CD, Stirling RW (1990) Intranodal myofibroblastoma presenting in submandibular region: evidence of a broader clinical and histological spectrum. Histopathology 16: 287–293 3. Griffiths AP, Ironside JW, Gray C (1991) True neurilemmoma arising in a lymph node in infancy. Histopathology 18: 180–183 4. Lee JY, Abell E, Shevechik GJ (1989). Solitary spindle cell tumor with myoid differentiation of the lymph node. Arch Pathol Lab Med 113: 547–550 5. Skalova A, Michal M, Chlumska A, Leivo I (1992) Collagen composition and ultrastructure of the so called amianthoid fibers in palisaded myofibroblastoma. Ultrastructural and immunohistochemical study. J Pathol 167: 335–40 6. Suster S, Rosai J (1989) Intranodal hemorrhagic spindlecell tumors with “amianthoid” fibers. Report of six cases of a distinctive mesenchymal neoplasm of the inguinal region that simulates Kaposi’s sarcoma. Am J Surg Pathol 13: 347–357 7. Tanda F, Massarelli G, Cossu A, Bosincu L, Cossu S, Ibba M (1993) Primary spindle cell tumor of lymph node with amianthoid fibers: a histological, immunohistochemical and ultrastructural study. Ultrastruct Pathol 17: 195–205 8. Tsang WY, Chan JK, Dorfman RF, Rosai J (1994) Vasoproliferative lesions of lymph node. Pathol Annu 29(Pt1): 63–133 9. Warnke RA, Weiss LM, Chan JKC, Cleary ML, Dorfman RF (1995) Nonhematolymphoid tumors and tumor-like lesions of lymph node and spleen. In : Tumors of the lymph nodes and spleen. Atlas of Tumor Pathology, Armed Forces Institute of pathology, Third series, fascicle 14, pp 435–526 10. Weiss SW, Gnepp DR, Bratthauer GL (1989). Palisaded myofibroblastoma. A benign mesenchymal tumor of a lymph node. Am J Surg Pathol 13: 341–346
Received: Februar 8, 2001 Accepted in revised version: November 5, 2001
Teaching Case
RESEARCH AND PRACTICE © Urban & Fischer Verlag http://www.urbanfischer.de/journals/prp
Ancient Schwannoma Arising in a Lymph Node: Report of a Case and Review of the Literature S. Piana, M. C. Gelli, A. Cavazza, L. Serra, G. Gardini Servizio di Anatomia ed Istologia Patologica, Ospedale Santa Maria Nuova, Reggio Emilia, Italy
Summary
Clinical History
We report a case of an intranodal schwannoma in a 79year-old woman. The patient underwent a left colectomy for a colonic adenocarcinoma, with regional lymph node dissection. Macroscopic examination of the specimen revealed a well-circumscribed 4 cm nodule located in the pericolic fat. Macroscopically, it was interpreted as a metastatic lymph node. Microscopically, the nodule was composed of a proliferation of bland spindle cells, was immunohistochemically positive for S100 protein, and negative for smooth muscle actin, desmin, and cytokeratin. The pathological findings led to the diagnosis of a very rare case of primary schwannoma of the lymph node.
A 79-year-old woman with an unremarkable medical history presented with abdominal pain, distension and stipsi, and with heme-positive stools. A left colonic neoplasm was diagnosed by colonscopy, and a conventional adenocarcinoma was confirmed by histological examination of the endoscopic biopsies. Routine preoperative examination revealed neither metastatic localizations nor associated diseases. The patient underwent a left colectomy with regional lymph node dissection. The postoperative course was uneventful.
Results Key words: Schwannoma – Neurilemmoma – Lymph node – Palisaded myofibroblastoma – Immunohistochemistry
Introduction Schwannomas arising in lymph nodes are extremely rare [3, 9]. Some cases previously diagnosed as intranodal schwannomas have been reclassified as palisaded myofibroblastomas on the basis of some peculiar histological and immunohistochemical features [10]. Their importance mainly lies in the differentiation between a metastatic neoplasm and a primary tumor. In this case, the lesion was macroscopically interpreted as a lymph node metastasis of colonic adenocarcinoma. We report a case of an ancient schwannoma arising in an abdominal lymph node, and briefly review the literature on intranodal spindle cell neoplasms. Pathol. Res. Pract. 198: 51–54 (2002)
Gross examination of the colectomy specimen revealed an ulcerated neoplasm, 5 cm in greatest diameter, which was deeply invasive on cut sections. Eight lymph nodes were found in the adjacent pericolic fat. The largest node measured 4 × 3 × 3 cm, was well circumscribed, and was surrounded by a thin rim of fibrous capsule. The cut surfaces were yellowish with focal, microcystic areas. Microscopically the neoplasm was interpreted as an adenocarcinoma NOS, T3NO. All the lymph nodes were free of tumor invasion. The largest pericolic nodule was identified as a lymph node because of the presence of a
Address for correspondence: Simonetta Piana, Servizio di Anatomia ed Istologia Patologica, Ospedale Santa Maria Nuova, Viale Risorgimento 80, 42100 Reggio Emilia, Italy. Tel.: +39-522-295919, Fax: +39-522-296945. E-mail: [email protected] 0344-0338/02/198/1-51 $15.00/0
52 · S. Piana et al. 1
2
3
4
Ancient Schwannoma Arising in a Lymph Node · 53
Fig. 5. The spindle cells are strongly immunoreactive to S100 protein (A) and negative to smooth muscle actin (B). Internal positive controls are apparent.
peripheral rim of compressed lymphoid tissue arranged in follicles, with many subcapsular sinuses and high endothelial venules; its center was occupied by proliferating spindle cells (Fig. 1), with twisted nuclei and ill-defined cytoplasmic borders (Fig. 2). The spindle cells were mainly arranged in compact interlacing bundles, with focal palisading, reminiscent of Antoni A growth pattern, alternating with the loose texture of Antoni B pattern. Focally hyperchromatic, atypical nuclei were noted (Fig. 3), but neither necrotic areas nor mitoses were present. Degenerative changes were apparent, including microcyst formation, xanthomatous infiltration, and perivascular hyalinization (Fig. 4). Immunohistochemically, there was strong and diffuse staining of the spindle cells with antibody to S100 protein (Fig. 5A) and vimentin, with no antibody reactivity to smooth muscle actin (Fig. 5B) , desmin, CD34, and cytokeratin.
Discussion Primary non-lymphoid neoplasms of lymph nodes are quite uncommon. Among them, the occurrence of spindle cell neoplasms is often based only on “anecdote” and not fact. Their importance lies in the differentiation between metastasis from carcinomas or melanomas and a lymphadenopathic form of Kaposi’s sarcoma. Most spindle cell intranodal lesions are represented by the hemorrhagic spindle cell tumor with amianthoid fibers, also referred to as palisaded myofibroblastoma [6, 10]. The latter was first described in 1989, and was then reported occurring at many anatomical sites [1, 2, 4, 5, 7]. One of the largest series, including many lesions initially defined as intranodal schwannoma, was subsequently reviewed by Weiss et al. [10]. Palisaded myofibroblastoma is always characterized by stellate areas of collagen deposition, also called
Fig. 1. The lymph node is almost completely involved by solidly proliferating spindle cells; the capsule is unremarkable. Hematoxylin-eosin, × 20. Fig. 2. A peripheral rim of compressed lymphoid tissue is associated with a central proliferation of spindle cells with nuclear atypia. Hematoxylin-eosin, ×100. Fig. 3. Spindle cells with oval, hyperchromatic nuclei, haphazardly arranged. Hematoxylin-eosin, × 100. Fig. 4. Hyalinized vessels and pseudocystic degeneration. Hematoxylin-eosin, × 200.
54 · S. Piana et al.
“amianthoid fibers”, which are lacking in our case; strong immunohistochemical reactivity to smooth muscle actin and negativity to S100 protein confirm the myofibroblastic differentiation of the proliferating cells. Lymphadenopathic Kaposi’s sarcoma is a highly cellular lesion composed of fascicles of spindle cells intermingled with slits containing extravasated erythrocytes. The immunohistochemical profile, reminiscent of endothelial differentiation, the interspersed erythrocytes, and the typical eosinophilic hyaline globules allow for the correct diagnosis [9]. Several uncommon proliferative lesions originating from smooth muscle cells can occur in lymph nodes [8, 9]. They are occasionally found and mainly include leiomyoma, angiomyolipoma, leiomyomatosis, and lymphangioleiomyomatosis. Immunohistochemical features, along with the clinical setting, are helpful in rendering the correct diagnosis. Schwannomas arising in lymph node are very rare and have been reported only briefly [3] or just mentioned [5]. They typically show a proliferation of compact bundles of bland-looking spindle cells, sometimes exhibiting a whorled pattern and alternating with less cellular Antoni B areas. Immunohistochemically, S100 protein is easily demonstrated, while there is no evidence of smooth muscle or epithelial differentiation. In this case, all the hallmarks of schwannomas were present, along with some peculiar features, i.e., extensive hyalinization with cystic degeneration, and scattered spindle cells with hyperchromatic and tapered nuclei. These changes have been referred to as “ancient” features in schwannomas and do not imply any malignant transformation; nor do they have prognostic value. Differential diagnostically, one might also consider a nodal localization of a malignant peripheral nerve sheath tumor (MPNST) or a spindle cell melanoma. First, the clinical history and the clinical examination of the patient ruled out other neoplasms apart from colonic adenocarcinoma; second, MPNSTs and spindle cell melanomas can then be recognized on histological grounds alone because of their marked cellularity, mitotic activity, and cytological pleomorphism. Such a pleomorphism clearly resembles a sarcoma and differs from the degenerative changes of ancient schwannomas. In conclusion, we have reported a case of primary ancient schwannoma arising in a lymph node and macroscopically interpreted as a metastasis. Intranodal
schwannomas can therefore reproduce all the morphological features of schwannomas arising at extranodal sites and must be considered when it comes to diagnosing an intranodal spindle cell neoplasm.
References 1. Barbareschi M, Mariscotti C, Ferrero S, Pignatiello U (1990) Intranodal hemorrhagic spindle cell tumor: a benign Kaposi-like nodal tumor. Histopathology 17: 93–96 2. Fletcher CD, Stirling RW (1990) Intranodal myofibroblastoma presenting in submandibular region: evidence of a broader clinical and histological spectrum. Histopathology 16: 287–293 3. Griffiths AP, Ironside JW, Gray C (1991) True neurilemmoma arising in a lymph node in infancy. Histopathology 18: 180–183 4. Lee JY, Abell E, Shevechik GJ (1989). Solitary spindle cell tumor with myoid differentiation of the lymph node. Arch Pathol Lab Med 113: 547–550 5. Skalova A, Michal M, Chlumska A, Leivo I (1992) Collagen composition and ultrastructure of the so called amianthoid fibers in palisaded myofibroblastoma. Ultrastructural and immunohistochemical study. J Pathol 167: 335–40 6. Suster S, Rosai J (1989) Intranodal hemorrhagic spindlecell tumors with “amianthoid” fibers. Report of six cases of a distinctive mesenchymal neoplasm of the inguinal region that simulates Kaposi’s sarcoma. Am J Surg Pathol 13: 347–357 7. Tanda F, Massarelli G, Cossu A, Bosincu L, Cossu S, Ibba M (1993) Primary spindle cell tumor of lymph node with amianthoid fibers: a histological, immunohistochemical and ultrastructural study. Ultrastruct Pathol 17: 195–205 8. Tsang WY, Chan JK, Dorfman RF, Rosai J (1994) Vasoproliferative lesions of lymph node. Pathol Annu 29(Pt1): 63–133 9. Warnke RA, Weiss LM, Chan JKC, Cleary ML, Dorfman RF (1995) Nonhematolymphoid tumors and tumor-like lesions of lymph node and spleen. In : Tumors of the lymph nodes and spleen. Atlas of Tumor Pathology, Armed Forces Institute of pathology, Third series, fascicle 14, pp 435–526 10. Weiss SW, Gnepp DR, Bratthauer GL (1989). Palisaded myofibroblastoma. A benign mesenchymal tumor of a lymph node. Am J Surg Pathol 13: 341–346
Received: Februar 8, 2001 Accepted in revised version: November 5, 2001