Cell Carcinoma Of Hypercalcemic Type Research Articles

SMARCA4-Deficient Carcinoma of Uterine Cervix Resembling SCCOHT—Case Report

Small cell carcinoma of hypercalcemic type (SCCOHT) is a rare gynaecological neoplasm, originating mostly in the ovaries. Cervical origin of this very aggressive malignancy with unknown histogenesis is an extremely rare condition, without published management recommendations. Alterations in SMARCA4 gene are supposed to play the major role in SCCOHT oncogenesis and their identification is crucial for the diagnosis. Adequate genetic counselling of the patients and their families seems to be of great importance. Optimal management and treatment approaches are not known yet but may extremely influence the prognosis of young female patients that suffer from this very resistant disease. Nowadays, a translational research seems to be the key for the further diagnostic and treatment strategies of SCCOHT. The purpose of the case report is to provide practical information and useful recommendations on the diagnosis, management, and treatment of SMARCA4-deficient carcinoma of the uterine cervix resembling SCCOHT.

Dysgerminoma of the Ovary: An Analysis of 140 Cases Emphasizing Unusual Microscopic Findings and Resultant Diagnostic Problems.

One-hundred fourty pure dysgerminomas were evaluated with particular focus on the microscopic features as seen in 125 cases with available slides. The patients ranged from 8 to 59 years of age (mean, 24.1 y). The tumors, bilateral in 4% of the cases and with a mean tumor diameter of 13 cm, were typically soft, lobulated, homogeneous, and creamy white to tan to yellow but necrosis was found in 13%, hemorrhage in 20%, and focal cystic change in 15%. On microscopic examination, the patterns and other notable features encountered, including their frequency, were as follows: an alveolar pattern resulting from delicate fibrovascular septa (51%), diffuse (33%), macronodular (14%), insular (26%), cords (28%), solid tubular (17%), microspaces (sometimes simulating glands) (12%), follicle-like spaces (5%), prominent fibrous bands (65%), stromal edema (56%), stromal luteinization (9%), granulomatous infiltrate (46%), lymphocytic infiltrate (100%), Langhans cell type giant cells (35%), syncytiotrophoblast giant cells (6%), prominent population of cells with pale to clear cytoplasm (73%), cells with amphophilic to eosinophilic cytoplasm (53%) and vacuolated occasionally signet ring-like cells (7%). Various constellations of the above findings often resulted in an appearance different from that usually portrayed in the literature and certain tumors of very different nature being in the differential such as undifferentiated carcinoma not otherwise specified, small cell carcinoma of hypercalcemic type, and malignant lymphoma. The correct diagnosis can be arrived at by considering the usual relative youth of the patient, often rather characteristic gross features, and most crucially careful attention to the microscopic features and awareness of variant morphologic findings. Those that are particularly problematic based on this study are diffuse growth with inconspicuous fibrovascular septa, macronodules, cords, solid tubular formations, spaces ranging from small to large, and mimicking glands or follicles, prominent fibrous to edematous stroma, and cells with amphophilic to eosinophilic cytoplasm. According to the degree of difficulty and confidence of the interpreter, well-known immunohistochemical features of dysgerminoma, which largely differ from those of other neoplasms in the differential, will aid if felt indicated.

Update on SWI/SNF-related gynecologic mesenchymal neoplasms: SMARCA4-deficient uterine sarcoma and SMARCB1-deficient vulvar neoplasms.

Our knowledge regarding the role of genes encoding the chromatin remodeling switch/sucrose non-fermenting (SWI/SNF) complex in the initiation and progression of gynecologic malignancies continues to evolve. This review focuses on gynecologic tumors in which the sole or primary genetic alteration is in SMARCA4 or SMARCB1, two members of the SWI/SNF chromatin remodeling complex. In this review, we present a brief overview of the classical example of such tumors, ovarian small cell carcinoma of hypercalcemic type, and then a detailed review and update of SMARCB1-deficient and SMARCA4-deficient tumors of the uterus and vulva.

Les tumeurs héréditaires de l’ovaire vues par le pathologiste

About 23% of adnexal tumors are related to a hereditary syndrome, most often hereditary breast and ovarian cancer syndrome or Lynch syndrome, responsible of epithelial tumors. However, the pathologist should be aware of rare hereditary syndromes responsible of non-epithelial ovarian tumors. Ovarian tumors associated with germline mutation of BRCA genes are essentially high-grade serous carcinomas of tubal origin, while those seen in Lynch syndrome are most often endometrioid or clear cell carcinomas. Sex-cord tumors associated with a familial predisposition are Sertoli-Leydig cell tumors in DICER syndrome and sex-cord tumors with annular tubules in Peutz-Jeghers syndrome. Small cell carcinoma of hypercalcemic type may be associated with a rhabdoid tumor predisposition syndrome 2. Finally, rare germ cell tumors have been reported related to ataxia telangiectasia. The recognition of these entities by pathologists is crucial. Even though the morphologic features pointing toward an inherited mutation may vary depending on the syndrome, the diagnosis may contribute to refer the patient for genetic counselling, modifying the management and follow-up of the patient and her family.

SCCOHT/tumeur rhabdoïde ovarienne : à propos d’un cas

We report the case of a 22-year-old patient with acute abdominopelvic pain. The diagnosis of hypercalcemic small cell carcinoma (SCCOHT)/ovarian rhabdoid tumor has been made. Small cell carcinoma of hypercalcemic type is a rare and aggressive tumor that occurs in young women. The diagnosis of this tumor and the management must be rapid in view of its aggressiveness. Through this observation, we specify the epidemiological, diagnostic, molecular aspects and discussions about its name.

Claudin-4 expression distinguishes SWI/SNF complex-deficient undifferentiated carcinomas from sarcomas

Inactivation of SWI/SNF (switch/sucrose non-fermentable) chromatin remodeling complex subunits is a feature shared by select carcinomas and sarcomas with epithelioid morphology and variable keratin expression, making the distinction between carcinoma and sarcoma challenging in some cases. The tight junction-associated protein claudin-4 is a marker of epithelial differentiation that is expressed in nearly all carcinomas. Claudin-4 expression has been reported in the glandular component of biphasic synovial sarcoma but has not been systematically evaluated in other sarcoma types. In this study we assessed claudin-4 expression in SWI/SNF complex-deficient neoplasms showing loss of SMARCB1 (INI1), SMARCA4 (BRG1), or ARID1A and other sarcomas with epithelioid morphology. Immunohistochemistry for claudin-4 was performed on 130 neoplasms, including 90 soft tissue tumors with epithelioid morphology and/or SMARCB1 deficiency (20 epithelioid sarcomas (10 conventional, 10 proximal-type); 10 epithelioid angiosarcomas; 10 epithelioid hemangioendotheliomas; 15 epithelioid malignant peripheral nerve sheath tumors; 10 malignant rhabdoid tumors; 15 myoepithelial carcinomas; 10 biphasic synovial sarcomas), 10 ovarian clear cell carcinomas, 10 ovarian small cell carcinomas of hypercalcemic type, and 20 SWI/SNF complex-deficient undifferentiated carcinomas (14 SMARCB1 deficient and 6 SMARCA4 deficient, including rhabdoid carcinomas of various sites and sinonasal carcinomas). Membranous expression of claudin-4 (≥5% of cells) was observed in all biphasic synovial sarcomas (epithelial component only), all ovarian clear cell carcinomas, and 16 (80%) SWI/SNF complex-deficient undifferentiated carcinomas. All other soft tissue tumors were negative for claudin-4, with the exception of two myoepithelial carcinomas and one malignant rhabdoid tumor. Interestingly, none of the ovarian small cell carcinomas of hypercalcemic type expressed claudin-4. In summary, expression of claudin-4 is highly specific for true epithelial differentiation and may be useful to distinguish SWI/SNF complex-deficient undifferentiated carcinomas from sarcomas with epithelioid morphology. The lack of claudin-4 expression in ovarian small cell carcinomas of hypercalcemic type suggests that these tumors may be better regarded as sarcomas rather than carcinomas.

Germline SMARCA4 mutations in patients with ovarian small cell carcinoma of hypercalcemic type.

BackgroundSMARCA4 mutations have recently been identified as driving lesions of the ovarian small cell carcinoma of hypercalcemic type (SCCHT). Familial occurrence of this neoplasm was described previously.MethodsWe looked for germline SMARCA4 alterations in eight patients with the SCCHT. DNA was extracted from probands’ and their relatives’ blood. The SMARCA4 coding sequence, previously found altered in all the tumors, was PCR amplified and sequenced in the germline DNA.ResultsTwo patients carried a heterozygous germline SMARCA4 alteration: c.3760G > T and c.2352insG, respectively. The analysis of the probands’ next of kins revealed that the c.3760G > T mutation was inherited by the proband and her sister from their father, and the sisters’ four children also carried the mutation. The proband’s sister was diagnosed with a carcinoma of the parotid gland at age 2. A brother of the other proband was tested negative.ConclusionsOur study suggests that some women develop the ovarian SCCHT due to the inherited or possibly de novo-occurring germline alterations in the SMARCA4 gene, however, its penetrance appears limited. Nevertheless, because of high aggressiveness of the SCCHT, a molecular diagnostics of the SMARCA4 gene and careful follow-up should be offered to patients with this cancer and their families.

Ovarian tumors and tumor-like lesions in the first three decades.

The relative frequency of ovarian tumors and tumor-like lesions that occur in young females (defined in this article as up to 30 years of age) differs considerably from that seen in older patients. The spectrum of lesions encountered is reviewed, with emphasis on those disproportionately seen in younger patients, particularly primitive germ cell tumors, certain tumors in the sex cord-stromal family, the distinctive tumor known as small cell carcinoma of hypercalcemic type, and selected tumor-like lesions. Comments are made initially on the relative frequency of the various well-known categories of ovarian neoplasia in the first three decades, compared to females overall, and differences within the first three decades are noted. Some of the more noteworthy of these include the occurrence of follicular cysts in neonates due to in-utero maternal stimulation, and the often large size of these lesions, with sometimes dramatic clinical manifestations; the relative rarity of the commonest germ cell tumor of the ovary, the dermoid cyst, in the very early years of life; the peak incidence of all primitive germ cell tumors in the mid to late teens and early 20s; the peak of small cell carcinoma of hypercalcemic type in the early 20s; the preponderance for the juvenile granulosa cell tumor to occur in the first two decades and for one distinctive form of Sertoli-Leydig cell tumor, the retiform variant, to peak at about 15 years of age; the occasional finding of mucinous cystic tumors, usually benign, in the teenage years, and their greater frequency than other surface epithelial neoplasms; a gradual increase in frequency of all types of surface epithelial neoplasia, but particularly mucinous tumors and serous tumors as patients move through the 20s; and the rarity of metastatic neoplasia in the first three decades in general, but with occasional dramatic examples such as some Krukenberg tumors being seen in these years, as may some of the distinctive tumors of the young such as neuroblastoma. Consideration of the gross and microscopic features, and differential diagnosis, of individual neoplasms follows the introductory remarks and emphasizes the importance of gross pathology. An example of the latter is the marked difference in most cases between a dermoid cyst and an immature teratoma, the former being dominantly cystic and the latter dominantly solid, and the latter on average twice as large as the former. Caution should be exercised in entertaining a diagnosis of immature teratoma if a lesion is grossly a typical dermoid cyst. The treacherous shared gross characteristics and age distribution of the dysgerminoma and small cell carcinoma of hypercalcemic type are noted. The rarity of monodermal teratomas and malignant neoplasms such as squamous cell carcinoma arising in dermoid cysts in the first three decades is noted. The distinctive features of two recently described stromal neoplasms, microcystic stromal tumor and luteinized thecomas of the type associated with sclerosing peritonitis, are emphasized as is the varied differential diagnosis of the juvenile granulosa cell tumor and Sertoli-Leydig cell tumor. Sections on ovarian tumors and tumor-like lesions in pregnant patients and tumor-like lesions overall conclude the article.

Ovarian small cell carcinoma of hypercalcemic type – evidence of germline origin and smarca4 gene inactivation. a pilot study

Ovarian tumors from two patients, compatible by histological and immunohistochemical criteria with small cell carcinoma of hypercalcemic type (SCCHT) (WT1+, EMA dispersed+, synaptophysin+ or dispersed+), were extensively sampled in order to find clues to their histogenesis. Subsequently, small foci of immature teratoma were found in both of them (in 1/122 and in 3/80 tumor sections). In one case, microfoci of yolk sac tumor were also present within the teratoma area as well as in the background of the small cell tumor population - in the primary tumor and in omental metastasis. We found a resemblance of the microscopic patterns of SCCHT and atypical teratoid/rhabdoid tumor (AT/RT) of the central nervous system, and this prompted us to evaluate INI-1 and SMARCA4 immunohistochemical expression, because their alternative loss is regarded as a molecular hallmark of AT/RT. INI-1 expression was retained, while that of SMARCA4 was lost. We therefore analyzed tumor DNA by PCR amplification and sequencing for mutations in the SMARCA4 gene (NG_011556.1), which were identified in both tumors (c.2184_2206del; nonsense c.3277C>T - both in one tumor; nonsense c.3760G>T in another tumor). These data suggest that SCCHT is most likely an embryonal tumor originating from immature teratoma and related to malignant rhabdoid tumor. Further analyses are necessary to determine whether the tumors diagnosed as SCCHT constitute a homogeneous group or represent more than one entity.

Small Cell Carcinoma of the Ovary of Hypercalcemic Type: A Case Report

Introduction. The small cell carcinoma of hypercalcemic type of ovary is a very aggressive tumor. It is associated with two-thirds of cases with hypercalcemia most often asymptomatic. It occurs mostly for young women. The treatment combines surgery, chemotherapy, and radiotherapy. Case Presentation. We report a case of small cell carcinoma of the ovary hypercalcemic type in a young Tunisian woman aged 25 years after a severe abdominal pain syndrome and a large ovarian mass discovered in scanner; a laparotomy was performed by radical surgery. The pathological examination of the specimen confirmed the diagnosis. The radiological assessment performed after surgery showed a continuing evolution. Palliative chemotherapy was established, and the patient had died two months after diagnosis. Conclusion. The hypercalcemic small cell carcinoma of the ovary is a rare disease of poor prognosis.

WT1 Expression in the Female Genital Tract

The Wilms tumor gene 1 (WT1) has been reported in normal tissues and many neoplasms of the female genital tract. This review discusses WT1 expression in the female genital tract and its potential utility in the differential diagnosis of neoplasms that occur at this location. WT1 is of value in the differential diagnosis of synchronous serous carcinomas arising in the ovary/fallopian tube/peritoneum and endometrium, as strong WT1 positivity in both tumors points toward an extrauterine origin. In addition, WT1 can be used to distinguish sex cord stromal tumors (WT1 positive) from endometrioid carcinomas (OECs). WT1 expression is not helpful in the differential diagnosis of ovarian serous carcinomas (OSCs) and transitional carcinomas, as both are typically positive and has limited value in the distinction of serous tumors arising in the ovary/fallopian tube/peritoneum from mesotheliomas. WT1 is also not helpful to differentiate small cell carcinoma of hypercalcemic type from juvenile granulosa cell tumor, a common diagnostic problem. Intra-abdominal desmoplastic round cell tumor reacts to WT1 (C-terminal) in contrast to all other tumors discussed which helps to separate this rare tumor from most other small round cell tumors that may involve, primarily or secondarily, the ovary with the exception of small cell carcinoma of hypercalcemic type that typically reacts with the N-terminal of WT1.

Borderline Ovarian Mucinous Neoplasm Recurring as Small Cell Carcinoma of Hypercalcemic Type

Ovarian small cell carcinoma of hypercalcemic type (OSCCHT) is an uncommon neoplasm of uncertain histogenesis. As far as we are aware, this neoplasm has never been reported in association with another primary ovarian tumor. We report a case in a 33-year-old patient in whom an extraovarian pericolonic neoplasm with the morphological features and immunohistochemical profile of OSCCHT developed 5 years after removal of an ovarian mucinous borderline tumor of the intestinal type. Together with the observation that mucinous epithelium is seen in some OSCCHTs, this case raises the possibility that this enigmatic neoplasm is of epithelial origin and is related to primary ovarian mucinous neoplasms. The pericolonic tumor exhibited an unusual immunophenotype with positive staining with CD99 and FLI-1, suggesting the possibility of a neoplasm in the Ewing family of tumors. This was excluded by molecular studies that showed no evidence of EWS/FLI-1 or EWS/ERG translocation.

Ovarian small cell carcinoma of hypercalcaemic-type: History of the disease in a patient who refused treatment

Ovarian small cell carcinoma of hypercalcaemic-type: History of the disease in a patient who refused treatment

Immunohistochemical markers as a diagnostic aid in ovarian pathology

With the advent of new antibodies and the discovery of novel applications of established markers, immunohistochemistry is increasingly being used in gynaecological pathology. Most of the applications in the field of ovarian pathology are related to the diagnosis of neoplasia; as yet, there are few situations where immunohistochemistry has proven useful in a prognostic or predictive sense. Immunohistochemistry is useful in distinguishing between a primary ovarian adenocarcinoma of endometrioid or mucinous type and a metastatic neoplasm from the colorectum, although it is stressed that many ovarian mucinous tumours express enteric markers, at least focally. In this distinction, a panel comprising CK7, CK20, CA125, CEA, ER and CDX2 is recommended. Markers may also be of value in distinguishing a primary ovarian adenocarcinoma from a metastasis from other sites but it is stressed that there is significant overlap in immunophenotype between pancreatic, biliary and gastric adenocarcinomas and primary ovarian mucinous carcinomas, a situation where there is not infrequently diagnostic confusion. The various markers discussed may also be of value in peritoneal biopsy or fluid specimens when faced with an adenocarcinoma of unknown primary. Immunohistochemistry is also useful in diagnosing other ovarian metastatic tumours, e.g. malignant melanoma, where the histological features may not be typical and the diagnosis not considered, especially in the absence of a known primary elsewhere. WT1 is useful in typing a primary ovarian carcinoma as most ovarian (and tubal and peritoneal) serous adenocarcinomas exhibit diffuse nuclear positivity while the other common types are typically negative, as is uterine serous carcinoma. As such, diffuse nuclear WT1 immunoreactivity in a disseminated serous carcinoma suggests an ovarian, peritoneal or tubal rather than a uterine origin. There are several useful markers of ovarian sex cord-stromal tumours, especially inhibin and calretinin, but also melan A and CD99. CD56 has recently been shown to be an extremely sensitive marker of ovarian sex cord-stromal tumours, although it lacks specificity. Immunohistochemistry may contribute to diagnosis in the broad fields of undifferentiated, spindle cell and small cell ovarian neoplasms; nuclear WT1 immunoreactivity is common in ovarian small cell carcinoma of hypercalcaemic type. Other areas where immunohistochemistry may contribute include the categories of neuroendocrine tumours and thyroid tissue (struma ovarii) with an unusual morphological appearance, including oxyphil or clear cells, such that thyroid tissue may not immediately spring to mind. There are several useful markers of malignant germ cell tumours, including established antibodies such as α-fetoprotein and placental alkaline phosphatase and relatively new markers, such as OCT4, which is positive in dysgerminoma and embryonal carcinoma. Throughout this review it is stressed that careful morphological examination, combined with consideration of the clinical and gross pathological features and judicious sampling, remains the mainstay in diagnosis. In problematic cases, a panel of markers should be carefully chosen based on the differential diagnoses under consideration; in this author’s experience, an inappropriate panel of markers is often chosen seemingly with little focus. It is stressed that unexpected staining may be encountered, one example being the recent discovery that TTF1, a hitherto considered reliable marker of thyroid and pulmonary neoplasms, is not uncommonly expressed in ovarian and other gynaecological adenocarcinomas.

Imprint cytology of high‐grade immature ovarian teratoma: A case report, literature review, and distinction from other ovarian small round cell tumors

Immature ovarian teratoma (IOT) is a rare and aggressive malignant neoplasm characterized by immature neural tissue. The cytomorphologic features have only rarely been described. We herein describe an additional case and review the literature regarding this entity. To the best of our knowledge, this is the first reported case with imprint cytology. A 35-year-old woman presented with a pelvic mass which was resected and sent for frozen section evaluation. Imprint smears and frozen section of the mass were diagnostic of IOT. IOT has diagnostic cytologic features which show complete concordance with histology. Differential diagnoses include other small round cell neoplasms such as ovarian neuroblastoma, small cell carcinoma of hypercalcemic type, primitive neuroectodermal tumor, Wilm's tumor, desmoplastic small round cell tumor, and Non-Hodgkin lymphoma. Distinguishing IOT from these tumors can be challenging however if diligent morphologic study and/or ancillary studies are performed accurate diagnosis is possible.

Small cell carcinoma of the ovary: clinical and biological study

Ovarian small cell carcinoma of hypercalcemic type is a rare neoplasm that typically occurs in young females. We describe three cases of ovarian small cell carcinoma of hypercalcemic type occurring in patients aged 24, 37, and 25 years. The first patient had stage IIc disease and had primary surgery with a left salpingo-oophorectomy and omentectomy, followed by chemotherapy with cisplatin and etoposide. Upon a second relapse, pelvic lymphadenectomy was performed, followed by chemotherapy with docetaxel. She is alive for 4 years without any recurrence after the initial treatment. In vitro drug-sensitivity assay revealed the tumor cells were sensitive to taxane and resistant to irinotecan. The second patient had stage III disease and had primary debulking surgery with bilateral salpingo-oophorectomy, simple hysterectomy, omentectomy, low-anterior resection, and lymphadenectomy, followed by chemotherapy with paclitaxel and carboplatin. Four months after the initial treatment she relapsed and died. The tumor cells were sensitive to platinum, taxane, and doxorubicin, but resistant to irinotecan. The third patient had stage III disease and had right salpingo-oophorectomy, omentectomy, and lymphadenectomy, followed by chemotherapy with cisplatin, cyclophosphamide, and doxorubicin. She relapsed 4 months after completing the chemotherapy and died 5 months after secondary debulking surgery. The tumor cells were sensitive to platinum, taxane, and doxorubicin, but resistant to irinotecan. The drug-sensitivity assays suggested that a non-irinotecan, taxane-containing combination might have been suitable as first-line chemotherapy for these patients. However, an effect of such a regimen was seen in only one patient with early-stage disease, and this questions the validity of chemosensitivity testing.

Selected miscellaneous ovarian lesions: small cell carcinomas, mesothelial lesions, mesenchymal and mixed neoplasms, and non-neoplastic lesions

This contribution will cover a variety of uncommon tumors and tumor-like lesions of the ovary that can be associated with a myriad of diagnostic problems for the pathologist. A few of these lesions are not specific to the ovary and may be more common in the uterus or even extraovarian sites, but the mere knowledge that they also occasionally occur in, or involve, the ovary will facilitate their recognition by the pathologist. In contrast, the entity considered first, the highly malignant small cell carcinoma of hypercalcemic type, is an enigmatic tumor unique to the ovary.

Selected miscellaneous ovarian lesions: small cell carcinomas, mesothelial lesions, mesenchymal and mixed neoplasms, and non-neoplastic lesions

This contribution will cover a variety of uncommon tumors and tumor-like lesions of the ovary that can be associated with a myriad of diagnostic problems for the pathologist. A few of these lesions are not specific to the ovary and may be more common in the uterus or even extraovarian sites, but the mere knowledge that they also occasionally occur in, or involve, the ovary will facilitate their recognition by the pathologist. In contrast, the entity considered first, the highly malignant small cell carcinoma of hypercalcemic type, is an enigmatic tumor unique to the ovary.

Ovarian Neoplasms Composed of Small Round Cells

Ovarian neoplasms composed predominantly or exclusively of small round cells with scant cytoplasm are relatively rare. However, there is a wide differential, and pathologists often struggle to make a correct diagnosis because of overlapping histologic features. Perhaps the best known of these neoplasms is ovarian small cell carcinoma of hypercalcemic type (OSCCHT), a tumor of unknown histogenesis. This may be confused with a wide range of neoplasms ranging from sex cord-stromal tumors (some of which may exhibit a small cell phenotype) to neoplasms in the family of small round blue cell tumors to various undifferentiated malignancies. A neuroendocrine small cell carcinoma, so-called small cell carcinoma of pulmonary type, may also arise within the ovary, and this may be a component of a typical ovarian surface epithelial-stromal tumor. In addition to the well-known family of small round blue cell tumors of childhood, other small cell neoplasms that may arise within the ovary or involve the ovary include intra-abdominal desmoplastic small round cell tumor, metastatic small cell carcinoma, peripheral and central primitive neuroectodermal tumor, and endometrial stromal sarcoma. Malignant melanoma, undifferentiated carcinoma, and various germ cell tumors, especially dysgerminoma and immature teratoma, also on occasion enter into the differential diagnosis of an ovarian small cell neoplasm. In this review, the morphologic features of some of these neoplasms are described, as is the value of immunohistochemistry and other ancillary techniques in establishing a diagnosis.

An immunohistochemical analysis of ovarian small cell carcinoma of hypercalcemic type.

Ovarian small cell carcinoma of hypercalcemic type (OSCCHT) is a rare neoplasm with an aggressive behavior, broad differential diagnosis, and unknown histogenesis. To add to knowledge concerning the possible aid of immunohistochemistry in resolving problems in differential diagnosis and to further explore whether that modality points to any specific histogenesis, we undertook an immunohistochemical study of this neoplasm. Fifteen OSCCHTs (including four of the ''large cell" variant) were stained with a range of antibodies, some of which have not been investigated previously in this neoplasm. Cases were stained with AE1/3, EMA, BerEP4, CK5/6, calretinin, WT1, chromogranin, CD56, synaptophysin, CD99, NB84, desmin, S100, CD10, alpha inhibin, TTFI, and p53. Staining was classified as 0 (negative), 1+ (<5% cells positive), 2+ (5% to 25% cells positive), 3+ (26% to 50% cells positive), or 4+ (>50% cells positive). All cases were positive with p53 (two 1+, five 3+, eight 4+), 14 of 15 cases were positive with WT1 (one 1+, thirteen 4+), 14 of 15 with CD10 (three 1+, four 2+, two 3+, five 4+), 13 of 15 with EMA (three 1+, three 2+, two 3+, five 4+), 11 of 15 with calretinin (nine 1+, one 3+, one 4+), 9 of 15 with AE1/3 (eight 1+, one 2+), 4 of 15 with CD56 (one 1+, two 2+, one 4+), 3 of 15 with BerEP4 (two 2+, one 4+), 2 of 15 with synaptophysin (two 1+), and 1 of 15 with S100 (4+). All cases were negative with CK5/6, chromogranin, CD99, NB84, desmin, alpha inhibin, and TTF1. The only noticeable difference in the immunophenotype between typical OSCCHT and the large cell variant was that there was 4 +EMA positivity in three of four cases of large cell variant compared with two of 11 cases of typical OSCCHT. OSCCHT is characteristically positive with AE1/3, EMA, CD10, calretinin, WT1, and p53. Combined EMA and WT1 positivity, the latter usually intense and diffuse, may be of diagnostic value, inasmuch as only a few of the neoplasms in the differential diagnosis are positive with both antibodies. Negative staining with CD99, desmin, NB84, alpha-inhibin, and TTF1 may aid in the cases in which primitive neuroectodermal tumor, rhabdomyosarcoma, intraabdominal desmoplastic small round cell tumor, neuroblastoma, a sex cord-stromal tumor, and metastatic pulmonary small cell carcinoma are in the differential. Calretinin positivity precludes its use in the differential with granulosa cell tumors. The results of this investigation do not settle the issue of histogenesis, which remains enigmatic. The typical age distribution, follicle formation, and calretinin positivity are consistent with a sex cord origin. On the other hand, WT1 and EMA positivity and negative staining with alpha-inhibin would be unusual in a sex cord-stromal neoplasm and can be used as an argument for a surface epithelial origin. Germ cell and neuroendocrine origins seem highly unlikely.