Immunocytochemical localization of calcitonin-producing cells in a strumal carcinoid with amyloid stroma

Neoplasms in Struma Ovarii: A Review

Struma ovarii is a well-known ovarian teratoma made up of benign thyroid tissue. These lesions demonstrate variable, normal architecture and normal thyroid immunohistochemical staining with positivity for TTF1, PAX8, and thyroglobulin. Though most are benign, some of these lesions can also present with a malignant component. Within this article, we review the most common diagnostic malignancies including papillary thyroid carcinoma, strumal carcinoid, highly differentiated follicular thyroid carcinoma, and other thyroid carcinomas. We additionally review the use of TTF1 staining to assist in differentiating these lesions from surrounding gynecologic epithelium, which is imperative in making such diagnoses. In highlighting these entities, we hope to provide practicing pathologists with an effective and concise review of these lesions to assist in more challenging cases of struma ovarii.

Immunohistochemical Profile and 47-Gene Next-Generation Sequencing (NGS) Solid Tumor Panel Analysis of a Series of 13 Strumal Carcinoids

Strumal carcinoid is an extraordinary rare tumor of the ovary consisting of thyroid tissue intermixed with neuroendocrine tumor component. The cellular origin of strumal carcinoids has been an area of debate. There is also little data on detailed immunohistochemical and molecular characteristics of these neoplasms. For this reason, this series investigated the characteristics of a series of 13 strumal carcinoids using immunohistochemical markers and a 47-gene next-generation sequencing (NGS) solid tumor panel analysis. Both cellular components showed thyroglobulin expression in all tumors. TTF-1 expression was noted in both cellular components of 11 cases. Chromogranin A was positive in both components of most tumors (n = 12, 92.3% in the neuroendocrine component and n = 10, 76.9% in the thyroid follicular component). Synaptophysin stained the neuroendocrine component of all cases, and it was also identified in the follicular thyroid component of a single case. All tumors were negative for CDX2 and calcitonin. ISLET1 was positive in the neuroendocrine component of 8 cases (6.5%). With the exception of one case, all tumors were positive for SSTR2a. The tumors were associated with a low Ki67 labeling index. All cases were microsatellite stable and no pathogenic mutations were identified using a 47-gene NGS solid tumor analysis. This series underscored that strumal carcinoids are distinct neuroendocrine tumors. The synchronous expression for thyroid follicular epithelial and neuroendocrine differentiation biomarkers may suggest a precursor cell origin displaying mixed-amphicrine differentiation. While strumal carcinoids can be diagnosed by their typical morphology and immunohistochemical profile, frequent SSTR expression may serve as a potential theranostic biomarker in the management of affected patients. In addition, the absence of common driver mutations in the NGS solid tumor panel may suggest that these neoplasms seem to be genetically unrelated to follicular epithelial-derived thyroid tumors and potentially different than other commonly identified well-differentiated neuroendocrine neoplasms. Therefore, further studies focusing on molecular characteristics of this entity are still needed.

The enigma of struma ovarii

Since its first description in the early part of the twentieth century, struma ovarii has elicited considerable interest because of its many unique features; however, at present a number of aspects remain enigmatic. Although the typical presentation is that of a pelvic mass, unusual clinical manifestations such as hyperthyroidism, ascites, and Meigs' syndrome have been recognised. Uncommon macroscopic and especially histological patterns in struma can cause difficulties in diagnosis. Cystic strumas are challenging to diagnose both macroscopically and histologically. Proliferative changes within struma can be misdiagnosed as cancer. In regard to the occurrence of thyroid-type carcinoma in struma ovarii, precise terminology should be utilised, and the term 'malignant struma ovarii' should be avoided because it has been used for several different pathological entities. Papillary carcinoma is the most commonly occurring thyroid-type carcinoma in ovarian struma; however, cases of follicular carcinoma are not infrequent. Histological malignancy in struma does not necessarily equate with biological malignancy, and the majority of thyroid-type carcinomas do not spread beyond the ovary. Strumal carcinoid, a neoplasm apparently unique to the ovary containing elements of both struma and carcinoid, has been misdiagnosed as 'malignant struma ovarii' in the past. The differential diagnosis of extra-ovarian spread of struma includes the usual types of thyroid cancer, minimal deviation follicular carcinoma, and peritoneal strumosis. This review emphasises articles both recent and past that have significantly advanced our knowledge of struma ovarii and related neoplasms.

Prostatic acid phosphatase in strumal carcinoids of the ovary. An immunohistochemical study

BACKGROUND

Strumal carcinoids (SC) are ovarian tumors containing thyroid parenchyma admixed with carcinoid elements. Microscopically, the carcinoid component of SC usually presents a ribbon or trabecular pattern similar to the pattern exhibited by hindgut carcinoids. The authors designed an immunohistochemical study to ascertain further similarities of the carcinoid component of SC to rectal carcinoids.

METHODS

Five cases of SC were examined by light microscopic study with hematoxylin and eosin and immunoperoxidase staining with a group of neurohormonal peptides, thyroglobulin, prostatic acid phosphatase, and prostate specific antigen.

RESULTS

All tumors were positive for thyroglobulin, chromogranin, prostatic acid phosphatase (PAP), and glucagon. They were consistently negative for prostate specific antigen and variably positive to the other antibodies.

CONCLUSIONS

The consistent positivity of the carcinoid component of SC to PAP immunostaining is a further similarity of these tumors to rectal carcinoids, in which positive immunostaining to PAP has been observed. The similarity is not well understood, however, as all evidence points to the origin of SC from germ cells in mature cystic teratomas without any embryologic relationship to the hindgut.

Peptide tyrosine tyrosine-positive ovarian carcinoid tumor arising from a dermoid cyst

A case of ovarian carcinoid tumor of the trabecular type is presented. The small carcinoid tumor was found incidentally in a resected dermoid cyst. Histologically, the tumor was surrounded by a smooth muscle layer with focal stromal invasion. Non-carcinoid papillary mucosa and a few small glands, simulating the mucosa of the fallopian tube and remnant müllerian glands, respectively, were also present adjacent to the carcinoid tumor and enclosed by the same smooth muscle layer. The tumor cells revealed argyrophilia, and were positive for peptide tyrosine tyrosine (PYY) in the cytoplasm and for CEA in part of the luminal surface. This case was considered to be a rare ovarian carcinoid tumor arising from a dermoid cyst, without association of struma ovarii. PYY may be a potential marker for determining the histogenesis of ovarian carcinoid tumors.

Hormone-producing tumors of the ovary

The ovary is an endocrine organ that gives rise to a wide variety of neoplastic and tumorlike nonneoplastic conditions, some of which are associated with endocrine activity. The hormones produced may be steroidal or nonsteroidal. The ovary is unique among endocrine organs in reacting to the presence of nonendocrine tumors within it by abnormal or inappropriate production of sex steroidal hormones. A classification of hormone-producing ovarian lesions is proposed based on the World Health Organization's histologicai typing of ovarian tumors.

Malignant struma ovarii: report of two cases and selected review of the literature

Malignant struma ovarii is an extremely rare tumor. Two new cases are described and current perspectives provided. Both cases are examples of the mixed form of the disease, and both were treated by surgery alone. One patient underwent total hysterectomy and bilateral salpingooophorectomy; the other had unilateral salpingo-oophorectomy. Both patients remained free of recurrent disease at 20 and 33 months from diagnosis. The controversies relating to therapy and diagnosis are discussed in detail.

Ectopic prolactin secretion from a gonadoblastoma

A 6.5-year-old girl developed isosexual, pseudoprecocious puberty secondary to a gonadoblastoma. The tumor was found to produce and secrete both immunoassayable and bioassayable prolactin based on immunohistochemical techniques and the presence of a prolactin gradient between the tumor vein and peripheral vein. The source of the prolactin was a Sertoli-like cell. Neither growth hormone nor growth hormone-releasing hormone was detected within the tumor. This case confirms the ectopic production of prolactin by neoplastic tissue.

Strumal carcinoid of the ovary. Ultrastructural and immunohistochemical study

Strumal carcinoid of the ovary with mucinous cystadenoma of borderline malignancy is reported. A colloid-like material in the follicular structure contained thyroglobulin which was immunohistochemically demonstrated to confirm the thyroid element, whereas the carcinoid component, which showed argyrophilia and displayed neurosecretory granules, revealed an insular or trabecular structure. This confirmed the presence of colloid filled thyroid epithelium intimately admixed with the carcinoid. Electron microscopy revealed carcinoid cells expanding toward the inner layer of the follicles but thyroid epithelium almost always stretched its thin cytoplasmic processes to cover the colloidal lumen. No calcitonin was demonstrated but CEA was seen in some cells of the carcinoid. No amyloid was detected.

Ovarian strumal carcinoid tumor with amyloid stroma--report of a case with 20-year follow-up

We report a case of strumal carcinoid tumor arising in the left ovary of a 20-year-old woman. Histologically, microfollicular, solid, and trabecular areas were present, and amyloid stroma was demonstrated. Many cells contained argyrophilic granules, and thyroglobulin and calcitonin were demonstrated immunohistochemically in several areas. Ultrastructurally the cells resembled thyroid follicular cells and contained neurosecretory granules. It is concluded that strumal carcinoid is of endodermal origin, and shows evidence of thyroid and C-cell differentiation.

Carcinoid tumour arising in a recurrent intradural spinal teratoma

We report the case of a recurrent intradural spinal teratoma in a 44-year-old woman. Histological examination showed the lesion to be composed entirely of mature elements including an argyrophil carcinoid tumour. Electron microscopy showed the neoplastic cells to possess the ultrastructural features of a foregut type APUDoma. Gamma enolase, a marker of APUD cells, was demonstrated in the neoplasm by the peroxidase-antiperoxidase technique. This method was also used to demonstrate the presence of cytokeratins in the neoplastic cells and the squamous and columnar epithelia within the teratoma. These results are consistent with the suggestion that APUD cells of foregut type may be of endodermal rather than neuroectodermal origin.

Carcinoid tumors of the ovary

Carcinoid tumors of the ovary are uncommon, but 150 cases of primary ovarian carcinoids and 40 cases of carcinoid tumors metastatic to the ovary have been reported. Primary carcinoid tumors of the ovary are divided into insular, trabecular, strumal and mucinous types. The insular type is most common, followed by the strumal type. The majority of primary ovarian carcinoids occur in association with mature cystic teratoma, but a considerable number present in pure form. Only the insular type is associated with the carcinoid syndrome. The age incidence of patients with ovarian carcinoids shows a wide range but most patients are postmenopausal. Primary carcinoids of the ovary are invariably unilateral. They form a solid nodule within a cystic teratoma, or when pure a solid yellow-grey mass, and vary from microscopical to large tumors measuring in excess of 20 cm in the longest diameter. The metastatic carcinoids are nearly always bilateral and scattered tumor deposits are present throughout both ovaries. Primary ovarian carcinoids metastasize only occasionally, and should be treated as ovarian tumors of low malignant potential.

Carcinoid tumour of the larynx. A report of two cases

Two cases of carcinoid tumours of the larynx are described. One was histologically a typical carcinoid whilst the other showed cellular atypia, numerous mitoses and invasion of the surrounding tissues. Both were argyrophilic but not argentaffin positive whilst electron microscopy demonstrated the presence of neurosecretory granules and amyloid. The previous literature on these rare tumours of the larynx is reviewed.

Malignant struma ovarii. Light and electron microscopic study

Malignant struma ovarii is a very rare tumor, consisting of a struma ovarii with malignant change. Only 17 examples with metastases have previously been reported. We present a case which involved both ovaries and produced multiple metastases. Microscopy and ultrastructure were identical to a mixed papillary and follicular carcinoma of the thyroid gland. Characteristic ultrastructural features of malignant struma ovarii are: microvilli on the surface and in the cytoplasmatic vacuoles; oncocytic transformation of cytoplasm of some cells; and presence of electron dense, granular and crystalline material (colloid) in the follicles and vacuoles. The patient's thyroid was normal. We conclude that malignant struma ovarii can only be diagnosed wheb a carcinoma arising in the thyroid gland can be excluded. Ultrastructure examination may provide useful diagnostic features separating malignant struma ovarii from strumal carcinoid and serous adenocarcinoma.

The diffuse endocrine system and derived tumours. Histological and histochemical characteristics

The Diffuse Endocrine System, to which the so-called APUD (Amine Precursor Uptake and Decarboxylation) cells do belong, gives rise to a group of tumours which may or not secrete amines and/or polypeptide hormones: carcinoids (argentaffinomas, argentaffin or Kultschitzky cell carcinomas). Foregut carcinoids are predominantly of B type (trabecular), argyrophilic, or non-reactive (in about 70% of cases) to silver impregnation. Midgut tumours are generally of A type (insular); more than 80% of them are argentaffinic. Hindgut derived carcinoids are primarily of mixed type; nearly 70% are non-reactive to silver stains. From a cytological standpoint all types may be build up of either small-round, spindle-shaped, polyhedral or cuboidal cells. From a functional point-of-view, the cells are either clear and immature, non-reducing or exhausted. Accordingly, the diagnosis cannot be based alone on silver impregnation or other histochemical methods.

Neurohormonal peptides in ovarian carcinoids: an immunohistochemical study of 81 primary carcinoids and of intraovarian metastases from six mid-gut carcinoids

Eighty-one primary ovarian carcinoids and intraovarian metastases from six mid-gut carcinoids were examined for the presence of tumor cells immunoreactive with antisera raised against various neurohormonal peptides, mostly of gastroenteropancreatic (GEP) origin. Twenty of the primary and two of the metastatic carcinoids contained such tumor cells. The incidence of tumors with any kind of neurohormonal peptide immunoreactive tumor cells was 53% in the trabecular carcinoids, and 42% in the strumal carcinoids, whereas the incidence was much lower (7%) in the insular type. Immunoreactive pancreatic polypeptide (PP), glucagon, enkephalin, and somatostatin were those neurohormonal peptides most commonly observed in the tumor cells of the primary carcinoids. Those less commonly found were substance P, calcitonin, VIP, neurotensin, beta-endorphin, and ACTH. Four metastatic carcinoids were nonreactive with all the antisera used. Cells storing immunoreactive insulin, glucagon, PP, VIP, gastrin, substance P, or enkephalin were found in one of the two remaining metastatic carcinoids; in the other only gastrin-immunoreactive tumor cells were observed. The occurrence and distribution of tumor cells storing the neurohormonal peptides in ovarian carcinoids are discussed in relation to their possible origin in the ovary and to carcinoids in the gut.

Strumal carcinoid of the ovary: an analysis of 50 cases of a distinctive tumor composed of thyroid tissue and carcinoid

Strumal carcinoid of the ovary is a type of germ-cell tumor characterized by an intimate mixture of thyroid tissue and carcinoid. Fifty patients with this type of tumor ranged in age from 21 to 77 years. The tumors measured up to 26 cm in diameter and were always unilateral. In 10% of the cases, the contralateral ovary contained another type of neoplasm, usually a dermoid cyst. Three-fifths of the strumal carcinoids arose in dermoid cysts or in mature solid teratomas. Birefringent calcium oxalate monohydrate crystals were commonly identified in the thyroid colloid, and argentaffin granules, in the carcinoid cells, thus substantiating the identity of the neoplastic components. Although 31% of the tumors were accompanied by focal stromal luteinization, only 8% of the cases exhibited clinical signs of steroid hormone production (endometrial hyperplasia, hirsutism, or virilism). In 8% of the cases, there was evidence suggesting functioning of the thyroid component, but no patient had the carcinoid syndrome. Only one woman died of tumour; five others died of unrelated causes. The remaining patients remained alive and well; 23, for at least five years, and 15, for at least ten years postoperatively. Although the carcinoid component of the strumal carcinoid has been considered a malignant transformation of struma ovarii, it is almost always benign, and treatment with a simple oophorectomy or salpingo-oophorectomy is effective.