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A rare case of follicular thyroid carcinoma in ovarian struma
case report
A RARE CASE OF FOLLICULAR THYROID CARCINOMA IN OVARIAN STRUMA Struma ovarii is a form of specialised mature teratoma, with predominantly mature thyroid tissue in an ovarian teratoma as seen in 2% of cases. Its malignant transformation is even rarer and is seen in only 5% of those cases. This 40-year-old female patient had an incidental nding of a pelvic mass during investigation of secondary amenorrhoea. She underwent a staging laparotomy and pelvic clearance. The histopathology revealed a bilateral mature teratoma of the ovary with follicular thyroid carcinoma in the right ovarian struma (malignant struma). A total thyroidectomy was performed followed by a whole body 131 I scintigraphy which did not reveal any abnormal uptake of isotope. The patient remains well after four years and is being followed-up with serial serum thyroglobulin surveillance.
P. Prasad1 D. Nunns1 C. S. Ubhi 2 Z. Chaudry I. Soomro3 1
Department of Gynaecology, Endocrine Surgery, 3 Histopathology Nottingham University Hospitals NHS Trust, City Hospital Campus, Hucknall Road, Nottingham NG5 1PB. 2
Correspondence to: Miss Padmini Prasad 40 Sandy Lane Bramcote hills Nottingham – NG9 3GS .UK Tel: + 44(0)2380219911 Fax: +44(0)2380219912 email: praminik@btinternet. com
keywords: mature teratoma ovary, malignant struma ovarii, follicular carcinoma of thyroid Surgeon, 1 October 2008, pp.313-15
Introduction
Case report
Mature cystic teratoma of the ovary is the most common germ cell tumour.1 Although 5% to 15% of benign ovarian teratomas contain some thyroid tissue, only 2% are composed exclusively of thyroid tissue and called struma ovarii.2,3,4 Though malignant transformation can occur from any of the embryonic germ layers, the most common malignancy arising in these otherwise benign tumours is sqamous cell carcinoma. Malignant transformation of ovarian struma is extremely rare. The diagnosis is invariably made post-operatively after the ovary has been removed. Subsequent management, involves a total thyroidectomy followed by whole body 131 I scintigraphy to identify any metastases and, if positive, treatment with radioiodine ablation. Follow-up is done with serial serum thyroglobulin measurement and scintigraphy. Recently it has been suggested to adopt a more precise histological terminology as papillary or follicular thyroid carcinoma in an ovarian struma, instead of ‘malignant struma ovarii’, to describe this enigmatic tumour.5 So far in the literature, there are only five reports wherein nearly the whole of struma is being replaced by follicular type thyroid carcinoma, as was seen in this patient.3 As malignant struma ovarii is a very rare gynaecological malignancy, all the knowledge about this condition is mainly from case reports.
A 40-year-old female patient presented with a history of amenorrhoea of eleven months. She had no significant past gynaecological history suggestive of polycystic ovarian syndrome, prolactinoma, thyroid dysfunction, gynaecological malignancies or any family history of premature menopause. On physical examination, she was obese (BMI of 39.4) and hirsute. Abdominal examination revealed a mobile, non-tender abdomino-pelvic mass equivalent to 20 weeks size pregnancy. All hormone profiles including the thyroid function tests and tumour markers were normal except for serum testosterone level of 7.3nmol/l (normal upper limit: 2.8nmol/l). An ultrasound scan showed a normal size uterus. There was a right adnexal mass measuring 108mm x 94mm x 100mm with a lobulated margin and central cystic areas along with curvilinear hyperechogenicity inferiorly. The left ovary could not be identified. The rest of the abdominal structures including the suprarenal glands were normal. The patient underwent a laparotomy which revealed a mass in the right ovary measuring 110mm x 100mm and another mass in the left ovary measuring 50mm x 40mm. The uterus was normal with neither ascites nor any evidence of secondaries in the abdomen and pelvis. A total abdominal hysterectomy and bilateral salpingo-oopherectomy with
© 2008 Surgeon 6; 5: 313-5
the royal colleges of surgeons of edinburgh and ireland | 313
Fig 2. Histopathology of the resected ovarian tumour showing an area of follicular thyroid carcinoma
Fig 1. An ultrasound scan picture revealing the right ovarian mass
omentectomy and multiple peritoneal biopsies was performed. We did not resort to lymph node dissection, as the risk of malignancy index score was low; the gross appearance of tumour was not suggestive of malignancy and there was absence of ascites or secondaries. Histopathology showed bilateral cystic teratoma of the ovaries. The left ovary showed a benign mature cystic teratoma. The right ovary was completely replaced by a solid/cystic mass with the solid area occupying nearly whole of the ovary. On microscopy, the cystic area contained spaces lined by both mature benign squamous and columnar epithelium with a small focus (approx 4mm) of benign thyroid tissue, but practically the rest of the tumour, which was solid, was replaced by malignant neoplasm that was composed of microfollicles filled with colloid (Figure 2) and stained positive with thyroglobulin immunostaining (Figure 3). The follicular lining cells had typical vesicular nuclei. There was infiltrative growth pattern with no obvious capsule and foci of vascular invasion (Figure 4). The tumour was just clear of the ovarian capsular surface. The right ovarian tumour was best classified as ‘malignant struma ovarii’ or as recently preferred terminology of ‘follicular type thyroid carcinoma in an ovarian struma’. The FIGO tumour stage was 1A as it was confined to a single ovary. All the other biopsies from peritoneum and omentum were negative. There was no other hormone secreting tumour component seen on special staining even though the patient showed clinical signs of increased testosterone production (hirsuitism, amenorrhoea and raised serum testosterone levels). Subsequently the surgical endocrinologist carried out a total thyroidectomy, followed by whole body radioactive iodine 131I scintigraphy to identify any abnormal uptake (suggesting metastasis), which would require ablative radioactive iodine therapy. The thyroidectomy specimen showed only a benign colloid nodule with no evidence of primary malignancy. The post-operative whole body 131I scan showed 0.11% of the administered dose taken up by the thyroid bed with no abnormal localisation of radioactive iodine elsewhere. The patient has been started on suppressive dose of thyroxin. Her testosterone level after surgery was normal at <1.7nmol/l. The reason for elevated preoperative testosterone level could not be ascertained. 314
|
Fig 3. Histopathology with positive immunoperoxidase staining for thyroglobulin
Discussion Mature cystic teratoma of the ovary is the most common germ cell tumour accounting for a third of all ovarian tumours and ninety-five per cent of these cases are benign. Usually unilateral, it is by definition composed of well-differentiated derivates (like teeth, hair, bone and thyroid tissue) which originate from all three germ cell layers and is most frequently diagnosed during the female reproductive period. A malignant transformation of the cystic teratoma is an uncommon complication and occurs in 1-2% of cases, most frequently in postmenopausal women.6 Though malignant transformation can occur from any of the embryonic germ layers, the most common malignancy arising in these otherwise benign tumours is ‘squamous cell carcinoma’.6,7 ‘Struma ovarii’, a form of specialised mature teratoma, is defined as replacement of 50% or more of the ovary with thyroid tissue or the presence of thyroid tissue as the predominant cell type in an ovarian tumour. Even though 5-15% of teratomas contain some thyroid tissue the incidence of struma ovarii is only 2%. A malignant transformation of struma ovarii is even rare and occurs in less than 5% of these cases. The follicular type thyroid carcinoma as in this patient is less common than the papillary type in the ovarian struma.3,5 Metastasis from malignant struma ovarii is rare and occurs in only 5-6% of cases. Though it behaves functionally like malignancy in its thyroid counterpart, the metastatic spread follows the pattern of an epithelial ovarian cancer. There is evidence that malignant struma ovarii behaves like its thyroid counterpart and cyto-reductive surgery followed by ablation with radioactive 131I has been advocated, even though some have proposed a wait-and-watch policy.2,3,4 As the histology following
the royal colleges of surgeons of edinburgh and ireland
© 2008 Surgeon 6; 5: 313-5
Fig 4. Inltrative growth pattern with no obvious capsule and foci of vascular invasion
her pelvic clearance demonstrated vascular invasion, a more extensive screening was essential in the form of whole-body 131I scintigraphy. Prior to this a total thyroidectomy was necessary not only to confirm normal thyroid, but also to facilitate nuclear medicine imaging, so that radioactive iodine uptake would occur mainly in metastatic thyroid tissue. Later this would also have potentiated 131I therapy if metastases were detected. However, in this patient a whole body 131I scan did not reveal any abnormal localisation of radioactive iodine. The majority of thyroid carcinoma in ovarian struma does not spread beyond the ovary.5 In addition, cases with no ovarian capsular involvement or metastases seem to have a good prognosis and hence we did not resort to 131I adjuvant therapy.4 As the reported cases of malignant struma ovarii are few, long-term prognosis is difficult to estimate. A review of the literature suggested that recurrence after treatment of malignant struma ovarii was seen on average after a period of four years and it is prudent to follow-up with thyroglobulin surveillance and radioactive iodine scintigraphy for at least ten years.8 Radioactive iodine ablation is considered if recurrence is detected and it can lead to an extended disease-free interval.9 Our patient remains well and disease-free after more than four years of follow-up.
REFERENCES 1. Wu Rt, Torng PL, Chang DY et al. Mature cystic teratoma of the ovary: a clinicopathlogic study of 283 cases. Zhonghua Yi Xue Za Zhi (Taipei) 1996; 58(4): 269-74 2. Christopher P. DeSimone, Subhod M. Lele and Susan C.Modesitt. Malignant struma ovarii: a case report and analysis of cases reported in the literature with focus on survival and I 131 therapy. Gynaecologic Oncology 89(2003): 543-48 3. Navarro MD, Tan MLA, Lovecchio JL et al. Case Report: Malignant struma ovarii. Annals of Clinical & Laboratory Science, vol.34, no.1, 2004; 107-11 4. Kabukcuoglu F, Baksu A, Yilmaz B et al. Malignant struma ovarii. Pathology Oncology Research vol 8, No 2, 2002; 145-47 5. Roth LM, Talerman A, ‘The enigma of Struma ovarii’. Pathology 2007; 39(1): 139-46 6. Christopherson WA, Councell RB. Malignant degeneration of a mature ovarian teratoma. Int J Gynaecology Obstet 1989; 30(4): 379-84 7. Levine DA, Villela JA, Poynor EA, Soslow RA. Gastro intestinal adenocarcinoma arising in a mature cystic teratoma of ovary. Gynecol Oncol 2004; 94(2): 597-93 8. Makani S, Kim W, Gaba AR.Struma ovarii with a focus of papillary thyroid cancer: a case report and review of the literature. Gynecol Oncol 2004; 94(3): 835-39 9. Brenner W, Bohuslavizki KH, Wolf H et al. Radiotherapy with iodine-131 in recurrent malignant struma ovarii. Euro J Nucl Med 1996; 23(1): 91-94
Conclusion This case has been reported for its rare clinical and histopathological presentation, in a ‘bilateral teratoma of ovary with follicular carcinoma change in a struma’. Due to the paucity of cases published, it is difficult to predict the natural progression of this disease, its management and the long-term prognosis. It is well worth remembering the very rare possible malignant change that can occur in a commonly occurring ovarian teratoma, as the clinical outcome changes dramatically.
Copyright 28 February 2008
© 2008 Surgeon 6; 5: 313-5
the royal colleges of surgeons of edinburgh and ireland | 315
A RARE CASE OF FOLLICULAR THYROID CARCINOMA IN OVARIAN STRUMA Struma ovarii is a form of specialised mature teratoma, with predominantly mature thyroid tissue in an ovarian teratoma as seen in 2% of cases. Its malignant transformation is even rarer and is seen in only 5% of those cases. This 40-year-old female patient had an incidental nding of a pelvic mass during investigation of secondary amenorrhoea. She underwent a staging laparotomy and pelvic clearance. The histopathology revealed a bilateral mature teratoma of the ovary with follicular thyroid carcinoma in the right ovarian struma (malignant struma). A total thyroidectomy was performed followed by a whole body 131 I scintigraphy which did not reveal any abnormal uptake of isotope. The patient remains well after four years and is being followed-up with serial serum thyroglobulin surveillance.
P. Prasad1 D. Nunns1 C. S. Ubhi 2 Z. Chaudry I. Soomro3 1
Department of Gynaecology, Endocrine Surgery, 3 Histopathology Nottingham University Hospitals NHS Trust, City Hospital Campus, Hucknall Road, Nottingham NG5 1PB. 2
Correspondence to: Miss Padmini Prasad 40 Sandy Lane Bramcote hills Nottingham – NG9 3GS .UK Tel: + 44(0)2380219911 Fax: +44(0)2380219912 email: praminik@btinternet. com
keywords: mature teratoma ovary, malignant struma ovarii, follicular carcinoma of thyroid Surgeon, 1 October 2008, pp.313-15
Introduction
Case report
Mature cystic teratoma of the ovary is the most common germ cell tumour.1 Although 5% to 15% of benign ovarian teratomas contain some thyroid tissue, only 2% are composed exclusively of thyroid tissue and called struma ovarii.2,3,4 Though malignant transformation can occur from any of the embryonic germ layers, the most common malignancy arising in these otherwise benign tumours is sqamous cell carcinoma. Malignant transformation of ovarian struma is extremely rare. The diagnosis is invariably made post-operatively after the ovary has been removed. Subsequent management, involves a total thyroidectomy followed by whole body 131 I scintigraphy to identify any metastases and, if positive, treatment with radioiodine ablation. Follow-up is done with serial serum thyroglobulin measurement and scintigraphy. Recently it has been suggested to adopt a more precise histological terminology as papillary or follicular thyroid carcinoma in an ovarian struma, instead of ‘malignant struma ovarii’, to describe this enigmatic tumour.5 So far in the literature, there are only five reports wherein nearly the whole of struma is being replaced by follicular type thyroid carcinoma, as was seen in this patient.3 As malignant struma ovarii is a very rare gynaecological malignancy, all the knowledge about this condition is mainly from case reports.
A 40-year-old female patient presented with a history of amenorrhoea of eleven months. She had no significant past gynaecological history suggestive of polycystic ovarian syndrome, prolactinoma, thyroid dysfunction, gynaecological malignancies or any family history of premature menopause. On physical examination, she was obese (BMI of 39.4) and hirsute. Abdominal examination revealed a mobile, non-tender abdomino-pelvic mass equivalent to 20 weeks size pregnancy. All hormone profiles including the thyroid function tests and tumour markers were normal except for serum testosterone level of 7.3nmol/l (normal upper limit: 2.8nmol/l). An ultrasound scan showed a normal size uterus. There was a right adnexal mass measuring 108mm x 94mm x 100mm with a lobulated margin and central cystic areas along with curvilinear hyperechogenicity inferiorly. The left ovary could not be identified. The rest of the abdominal structures including the suprarenal glands were normal. The patient underwent a laparotomy which revealed a mass in the right ovary measuring 110mm x 100mm and another mass in the left ovary measuring 50mm x 40mm. The uterus was normal with neither ascites nor any evidence of secondaries in the abdomen and pelvis. A total abdominal hysterectomy and bilateral salpingo-oopherectomy with
© 2008 Surgeon 6; 5: 313-5
the royal colleges of surgeons of edinburgh and ireland | 313
Fig 2. Histopathology of the resected ovarian tumour showing an area of follicular thyroid carcinoma
Fig 1. An ultrasound scan picture revealing the right ovarian mass
omentectomy and multiple peritoneal biopsies was performed. We did not resort to lymph node dissection, as the risk of malignancy index score was low; the gross appearance of tumour was not suggestive of malignancy and there was absence of ascites or secondaries. Histopathology showed bilateral cystic teratoma of the ovaries. The left ovary showed a benign mature cystic teratoma. The right ovary was completely replaced by a solid/cystic mass with the solid area occupying nearly whole of the ovary. On microscopy, the cystic area contained spaces lined by both mature benign squamous and columnar epithelium with a small focus (approx 4mm) of benign thyroid tissue, but practically the rest of the tumour, which was solid, was replaced by malignant neoplasm that was composed of microfollicles filled with colloid (Figure 2) and stained positive with thyroglobulin immunostaining (Figure 3). The follicular lining cells had typical vesicular nuclei. There was infiltrative growth pattern with no obvious capsule and foci of vascular invasion (Figure 4). The tumour was just clear of the ovarian capsular surface. The right ovarian tumour was best classified as ‘malignant struma ovarii’ or as recently preferred terminology of ‘follicular type thyroid carcinoma in an ovarian struma’. The FIGO tumour stage was 1A as it was confined to a single ovary. All the other biopsies from peritoneum and omentum were negative. There was no other hormone secreting tumour component seen on special staining even though the patient showed clinical signs of increased testosterone production (hirsuitism, amenorrhoea and raised serum testosterone levels). Subsequently the surgical endocrinologist carried out a total thyroidectomy, followed by whole body radioactive iodine 131I scintigraphy to identify any abnormal uptake (suggesting metastasis), which would require ablative radioactive iodine therapy. The thyroidectomy specimen showed only a benign colloid nodule with no evidence of primary malignancy. The post-operative whole body 131I scan showed 0.11% of the administered dose taken up by the thyroid bed with no abnormal localisation of radioactive iodine elsewhere. The patient has been started on suppressive dose of thyroxin. Her testosterone level after surgery was normal at <1.7nmol/l. The reason for elevated preoperative testosterone level could not be ascertained. 314
|
Fig 3. Histopathology with positive immunoperoxidase staining for thyroglobulin
Discussion Mature cystic teratoma of the ovary is the most common germ cell tumour accounting for a third of all ovarian tumours and ninety-five per cent of these cases are benign. Usually unilateral, it is by definition composed of well-differentiated derivates (like teeth, hair, bone and thyroid tissue) which originate from all three germ cell layers and is most frequently diagnosed during the female reproductive period. A malignant transformation of the cystic teratoma is an uncommon complication and occurs in 1-2% of cases, most frequently in postmenopausal women.6 Though malignant transformation can occur from any of the embryonic germ layers, the most common malignancy arising in these otherwise benign tumours is ‘squamous cell carcinoma’.6,7 ‘Struma ovarii’, a form of specialised mature teratoma, is defined as replacement of 50% or more of the ovary with thyroid tissue or the presence of thyroid tissue as the predominant cell type in an ovarian tumour. Even though 5-15% of teratomas contain some thyroid tissue the incidence of struma ovarii is only 2%. A malignant transformation of struma ovarii is even rare and occurs in less than 5% of these cases. The follicular type thyroid carcinoma as in this patient is less common than the papillary type in the ovarian struma.3,5 Metastasis from malignant struma ovarii is rare and occurs in only 5-6% of cases. Though it behaves functionally like malignancy in its thyroid counterpart, the metastatic spread follows the pattern of an epithelial ovarian cancer. There is evidence that malignant struma ovarii behaves like its thyroid counterpart and cyto-reductive surgery followed by ablation with radioactive 131I has been advocated, even though some have proposed a wait-and-watch policy.2,3,4 As the histology following
the royal colleges of surgeons of edinburgh and ireland
© 2008 Surgeon 6; 5: 313-5
Fig 4. Inltrative growth pattern with no obvious capsule and foci of vascular invasion
her pelvic clearance demonstrated vascular invasion, a more extensive screening was essential in the form of whole-body 131I scintigraphy. Prior to this a total thyroidectomy was necessary not only to confirm normal thyroid, but also to facilitate nuclear medicine imaging, so that radioactive iodine uptake would occur mainly in metastatic thyroid tissue. Later this would also have potentiated 131I therapy if metastases were detected. However, in this patient a whole body 131I scan did not reveal any abnormal localisation of radioactive iodine. The majority of thyroid carcinoma in ovarian struma does not spread beyond the ovary.5 In addition, cases with no ovarian capsular involvement or metastases seem to have a good prognosis and hence we did not resort to 131I adjuvant therapy.4 As the reported cases of malignant struma ovarii are few, long-term prognosis is difficult to estimate. A review of the literature suggested that recurrence after treatment of malignant struma ovarii was seen on average after a period of four years and it is prudent to follow-up with thyroglobulin surveillance and radioactive iodine scintigraphy for at least ten years.8 Radioactive iodine ablation is considered if recurrence is detected and it can lead to an extended disease-free interval.9 Our patient remains well and disease-free after more than four years of follow-up.
REFERENCES 1. Wu Rt, Torng PL, Chang DY et al. Mature cystic teratoma of the ovary: a clinicopathlogic study of 283 cases. Zhonghua Yi Xue Za Zhi (Taipei) 1996; 58(4): 269-74 2. Christopher P. DeSimone, Subhod M. Lele and Susan C.Modesitt. Malignant struma ovarii: a case report and analysis of cases reported in the literature with focus on survival and I 131 therapy. Gynaecologic Oncology 89(2003): 543-48 3. Navarro MD, Tan MLA, Lovecchio JL et al. Case Report: Malignant struma ovarii. Annals of Clinical & Laboratory Science, vol.34, no.1, 2004; 107-11 4. Kabukcuoglu F, Baksu A, Yilmaz B et al. Malignant struma ovarii. Pathology Oncology Research vol 8, No 2, 2002; 145-47 5. Roth LM, Talerman A, ‘The enigma of Struma ovarii’. Pathology 2007; 39(1): 139-46 6. Christopherson WA, Councell RB. Malignant degeneration of a mature ovarian teratoma. Int J Gynaecology Obstet 1989; 30(4): 379-84 7. Levine DA, Villela JA, Poynor EA, Soslow RA. Gastro intestinal adenocarcinoma arising in a mature cystic teratoma of ovary. Gynecol Oncol 2004; 94(2): 597-93 8. Makani S, Kim W, Gaba AR.Struma ovarii with a focus of papillary thyroid cancer: a case report and review of the literature. Gynecol Oncol 2004; 94(3): 835-39 9. Brenner W, Bohuslavizki KH, Wolf H et al. Radiotherapy with iodine-131 in recurrent malignant struma ovarii. Euro J Nucl Med 1996; 23(1): 91-94
Conclusion This case has been reported for its rare clinical and histopathological presentation, in a ‘bilateral teratoma of ovary with follicular carcinoma change in a struma’. Due to the paucity of cases published, it is difficult to predict the natural progression of this disease, its management and the long-term prognosis. It is well worth remembering the very rare possible malignant change that can occur in a commonly occurring ovarian teratoma, as the clinical outcome changes dramatically.
Copyright 28 February 2008
© 2008 Surgeon 6; 5: 313-5
the royal colleges of surgeons of edinburgh and ireland | 315