Philip B. Clement

Mutation of FOXL2 in granulosa-cell tumors of the ovary

BACKGROUND Granulosa-cell tumors (GCTs) are the most common type of malignant ovarian sex cord-stromal tumor (SCST). The pathogenesis of these tumors is unknown. Moreover, their histopathological diagnosis can be challenging, and there is no curative treatment beyond surgery. METHODS We analyzed four adult-type GCTs using whole-transcriptome paired-end RNA sequencing. We identified putative GCT-specific mutations that were present in at least three of these samples but were absent from the transcriptomes of 11 epithelial ovarian tumors, published human genomes, and databases of single-nucleotide polymorphisms. We confirmed these variants by direct sequencing of complementary DNA and genomic DNA. We then analyzed additional tumors and matched normal genomic DNA, using a combination of direct sequencing, analyses of restriction-fragment-length polymorphisms, and TaqMan assays. RESULTS All four index GCTs had a missense point mutation, 402C-->G (C134W), in FOXL2, a gene encoding a transcription factor known to be critical for granulosa-cell development. The FOXL2 mutation was present in 86 of 89 additional adult-type GCTs (97%), in 3 of 14 thecomas (21%), and in 1 of 10 juvenile-type GCTs (10%). The mutation was absent in 49 SCSTs of other types and in 329 unrelated ovarian or breast tumors. CONCLUSIONS Whole-transcriptome sequencing of four GCTs identified a single, recurrent somatic mutation (402C-->G) in FOXL2 that was present in almost all morphologically identified adult-type GCTs. Mutant FOXL2 is a potential driver in the pathogenesis of adult-type GCTs.

An immunohistochemical analysis of endometrial stromal and smooth muscle tumors of the uterus: a study of 54 cases emphasizing the importance of using a panel because of overlap in immunoreactivity for individual antibodies.

The expression of desmin, h-caldesmon, calponin, CD10, CD34, CD99, inhibin, and keratin (AE1/3-Cam 5.2) was studied in 10 conventional leiomyomas, 9 highly cellular leiomyomas, 9 epithelioid smooth muscle tumors, 9 leiomyosarcomas, 10 endometrial stromal tumors (4 with smooth muscle metaplasia), and 7 uterine tumors resembling ovarian sex cord tumors (UTROSCTs). c-kit expression was tested in 10 endometrial stromal tumors, 7 UTROSCTs, and 9 leiomyosarcomas. Desmin was positive in almost all smooth muscle tumors except those of epithelioid type, which were positive in only about half of the cases. It also stained areas of smooth muscle differentiation in endometrial stromal tumors and five of seven UTROSCTs. h-caldesmon was positive in almost all nonepithelioid smooth muscle tumors and in areas of smooth muscle differentiation in endometrial stromal tumors; it was positive in only about half of the epithelioid smooth muscle tumors and negative in all UTROSCTs. Calponin was positive in most tumor types. CD10 was positive in nine of 10 endometrial stromal tumors and five of seven UTROSCTs, although very focally in the latter group. It was also expressed, however, in almost all leiomyosarcomas, almost 50% of highly cellular leiomyomas, and rarely in the other smooth muscle tumors. CD34 was negative in the tested tumors with rare exceptions. CD99 and inhibin were positive in four of seven and one of seven UTROSCTs. Keratin positivity was found in most (five of seven) UTROSCTs and occasionally in smooth muscle tumors (seven of 37). c-kit was negative in all endometrial stromal tumors, UTROSCTs, and leiomyosarcomas. The major conclusions of this study are as follows: 1) Pure endometrial stromal tumors are usually desmin negative. 2) In contrast to some previous studies, CD10 expression was often seen in smooth muscle tumors, including most leiomyosarcomas and almost half of highly cellular leiomyomas. As a result, a panel of CD10, h-caldesmon, and desmin should be used and will distinguish endometrial stromal tumors from highly cellular leiomyomas in most cases. 3) In contrast to a previous study, no significant differences in immunoreactivity were seen between h-caldesmon and desmin in tumors with smooth muscle differentiation. 4) The absence of h-caldesmon in UTROSCTs helps separate them from epithelioid smooth muscle tumors. 5) UTROSCTs may express epithelial, stromal, and smooth muscle markers, suggesting divergent differentiation. 6) Our study shows less frequent inhibin expression in the sex cord-like elements of the UTROSCTs than in other studies. 7) c-kit may help distinguish metastatic endometrial stromal tumors of the uterus (c-kit negative) from gastrointestinal stromal tumors (c-kit positive). 8) CD34, CD99, and keratin have no or minimal role in this area, but keratin positivity in smooth muscle tumors should not lead to their confusion with epithelial tumors.

Müllerian adenosarcoma of the uterus. A clinicopathologic analysis of ten cases of a distinctive type of müllerian mixed tumor.

The clinicopathologic features of 10 cases of a distinctive type of müllerian mixed tumor of the uterus are presented. With two exceptions, these tumors were discovered during the seventh to ninth decades. Most of them formed bulky polypoid growths that filled the endometrial cavity and produced vaginal bleeding. One tumor was an intramural mass. Low power microscopic examination revealed an admixture of benign appearing neoplastic glands and a sar‐comatous stroma, creating a striking resemblance to the cystosarcoma phyllodes of the breast. The glands were lined by a variety of müllerian epithelial cell types, chiefly endometrial and squamous. The stromal element resembled endometrial stromal sarcoma in 9 cases, and embryonal rhabdomyosarcoma (sarcoma botryoides) in 1. No invasion of the myometrium, blood vessels, or lymphatics was observed, except in 1 case in which the tumor penetrated deeply into the myometrium. Five tumors recurred in the vagina or uterus, 3 on multiple occasions. Only 1 case, in which the stroma appeared highly malignant, was complicated by metastasis. Because of their generally low grade of malignancy, these tumors, for which we propose the term “müllerian adenosarcoma,” should be distinguished from the more aggressive classic forms of müllerian mixed tumor, the carcinosarcoma and the sarcoma of the endometrium.

Non-endometrioid carcinomas of the uterine corpus: a review of their pathology with emphasis on recent advances and problematic aspects.

This review considers the clinical and pathologic features of the various histologic subtypes of endometrial carcinoma excluding those of pure endometrioid type, as the latter tumors were the subject of a previous contribution in the Journal (Vol. 9, No. 2). Non-endometrioid carcinomas, which account for about 10% of endometrial carcinomas, may pose a great array of problems in differential diagnosis, including their distinction not only from benign lesions but also endometrioid carcinoma and various tumors that may secondarily involve the uterine corpus. The most common subtypes are serous, mucinous, and undifferentiated. Rarer tumors are clear cell, squamous, transitional cell carcinomas, and a variety of poorly differentiated carcinomas with unusual forms of differentiation, such as hepatoid carcinoma, carcinomas with trophoblastic elements, and giant cell carcinoma. Mixed carcinomas, which are common, are also discussed, including those with a component of endometrioid carcinoma. The final section deals with endometrial involvement by metastatic tumors, lesions that, albeit rare, are sometimes neglected in the differential diagnosis of endometrial carcinomas. Important aspects emphasized are: (1) The potential for serous carcinoma to be mimicked by various forms of papillary endometrioid carcinoma. (2) The rarity of clear cell carcinoma and the greater frequency of clear cells in endometrioid carcinoma. (3) The frequency of mucinous epithelium in tumors of mixed cell type. (4) The frequency with which neoplastic mucinous epithelium originates from the endometrium. (5) The striking degree of differentiation of some squamous cell carcinomas. (6) The occasional predominance of non-endometrioid carcinomas (especially serous or undifferentiated carcinoma) within malignant mullerian mixed tumors. (7) The spectrum of reactive epithelial changes and other non-neoplastic abnormalities that may mimic serous or clear cell carcinoma.

Endometriosis of the intestinal tract: a study of 44 cases of a disease that may cause diverse challenges in clinical and pathologic evaluation

Endometriosis of the intestinal tract may mimic a number of diseases both clinically and pathologically. The authors evaluated 44 cases of intestinal endometriosis in which endometriosis was the primary pathologic diagnosis, and evaluated them for a variety of gross and histologic changes. Cases with preneoplastic or neoplastic changes were excluded specifically because they were the subject of a previous study. The patients ranged in age from 28 to 56 years (mean age, 44 years), and presenting complaints included abdominal pain (n = 15), an abdominal mass (n = 12), obstruction (n = 8), rectal bleeding (n = 2), infertility (n = 3), diarrhea (n = 2), and increasing urinary frequency (n = 1). The clinical differential diagnoses included diverticulitis, appendicitis, Crohns disease, tubo-ovarian abscess, irritable bowel syndrome, carcinoma, and lymphoma. Forty-two patients underwent resection of the diseased intestine and two patients underwent endoscopic biopsies. In 13 patients there were predominantly mural masses, which were multiple in two patients (mean size, 2.6 cm). In addition, 11 cases had luminal stenosis or strictures, six had mucosal polyps, four had submucosal masses that ulcerated the mucosa (sometimes simulating carcinoma), three had serosal adhesions, one had deep fissures in the mucosa, and one was associated with appendiceal intussusception. Involvement of the lamina propria or submucosa was identified in 29 cases (66%) and, of these, 19 had features of chronic injury including architectural distortion (n = 19), dense lymphoplasmacytic infiltrates (n = 7), pyloric metaplasia of the ileum (n = 1), and fissures (n = 1). Three cases had features of mucosal prolapse (7%), ischemic changes were seen in four (9%), and segmental acute colitis and ulceration were seen in four and six cases (9% and 13%) respectively. In 14 patients, endometriosis formed irregular congeries of glands involving the intestinal surface epithelium, mimicking adenomatous changes. Mural changes included marked concentric smooth muscle hyperplasia and hypertrophy, neuronal hypertrophy and hyperplasia, and fibrosis of the muscularis propria with serositis. Follow-up of 20 patients (range, 1–30 years; mean, 7.8 years) revealed that only two patients had recurrent symptoms. None of the patients developed inflammatory bowel disease. Endometriosis can involve the intestinal tract extensively, causing a variety of clinical symptoms, and can result in a spectrum of mucosal alterations. Because the endometriotic foci may be inaccessible to endoscopic biopsy or may not be sampled because of their focality, clinicians and pathologists should be aware of the potential of this condition to mimic other intestinal diseases.

Aggressive angiomyxoma of pelvic soft parts: A clinicopathologic study of nine cases

Nine cases of aggressive angiomyxoma (AAM) of the pelvic soft parts were studied by light and electron microscopy and immunohistochemistry. The tumors were confined to the vulva, vagina, pelvic floor, and perineum in the seven women. The perineum and the para-anal region were involved in the two men. The patients ranged in age from 18 to 63 years. Aggressive angiomyxoma presented as a slowly growing, polypoid or cyst-like tumor. Six of the nine cases were followed up; all of the tumors recurred within nine to 84 months, and one recurred for the second time at 144 months. Recurrences were attributed to incomplete tumor excision. None of the six patients died or had metastases. The aggressive angiomyxomas had infiltrative borders and rubbery, white or soft, gelatinous cut surfaces. Histologically, the lesions were composed of stellate and spindle-shaped neoplastic cells embedded in a collagenous and hyaluronic acid-containing stroma. Nuclear atypia and mitoses were absent. Typically, the lesions had an important vascular component, often displaying medial hypertrophy and vascular grouping. Ultrastructurally, the neoplastic cells resembled fibroblasts rather than myofibroblasts. They showed strong immunoreactivity for actin but were negative for S-100 protein, Factor VIII, carcinoembryonic antigen, and keratin. The morphoimmunocytochemical characteristics of AAM cells favor a fibroblastic origin and differentiation. Aggressive angiomyxoma should be distinguished from the more common benign and malignant myxoid neoplasms or tumor-like conditions of the pelvic soft parts. Recurrence of AAM may be avoided by wide, local excision.

Endometrial stromal tumors: an update on a group of tumors with a protean phenotype.

Summary: Endometrial stromal tumors are reviewed with emphasis on their wide morphologic spectrum and problems in differential diagnosis, highlighting issues that have received particular attention in the recent literature. These neoplasms are divided into two major categories—endometrial stromal nodules and endometrial stromal sarcomas—a distinction made on the basis of the lack of significant infiltration at the periphery of the former. The division of endometrial stromal sarcomas into low‐grade and high‐grade categories has fallen out of favor and the designation endometrial stromal sarcoma is now considered best restricted to neoplasms that were formally referred to as “low‐grade” stromal sarcoma. Endometrial sarcomas without recognizable evidence of a definite endometrial stromal phenotype, designated poorly differentiated “endometrial sarcomas,” are almost invariably high grade and often resemble the mesenchymal component of a malignant mullerian mixed tumor. Two features of endometrial stromal tumors that may cause confusion are smooth muscle differentiation and epithelial patterns. Cases in the former category often have a characteristic “starburst” pattern of collagen formation. The most common epithelial patterns resemble those seen in ovarian sex‐cord stromal tumors. Much less common is endometrioid gland differentiation. Some endometrial stromal tumors have a prominent fibrous or myxoid appearance and the myxoid tumors should be distinguished from myxoid leiomyosarcoma. Other unusual features of endometrial stromal tumors are also discussed. Lesions in the differential diagnosis of uterine endometrial stromal neoplasms include highly cellular leiomyoma, cellular intravenous leiomyomatosis, adenomyosis with sparse glands, metastatic carcinoma, and lymphoma. Endometrial stromal sarcomas at extrauterine sites may be primary or metastatic from a uterine tumor, the latter sometimes being occult and difficult to definitively establish, particularly if there is a history of a remote hysterectomy for “leiomyomas.” Endometrial stromal sarcomas of the ovary, whether primary or metastatic, may be difficult to distinguish from ovarian sex‐cord stromal tumors. Extragenital endometrial stromal sarcomas may be confused with diverse lesions such as gastrointestinal stromal tumors, hemangiopericytoma, lymphangiomyomatosis, or mesenchymal cystic hamartoma of the lung. Immunohistochemistry may play a role in evaluating these tumors and in some instances establishing the diagnosis although conventional light microscopic analysis suffices in the majority of cases. The unusual tumor, the “uterine tumor resembling an ovarian sex‐cord tumor,” is also considered in this review as it is almost certainly of endometrial stromal derivation in many cases. These neoplasms may have a striking resemblance to granulosa cell tumors or Sertoli cell tumors, including those with a retiform pattern, and have recently been shown to be frequently inhibin positive.

The pathology of endometriosis: a survey of the many faces of a common disease emphasizing diagnostic pitfalls and unusual and newly appreciated aspects.

Although the histologic diagnosis of endometriosis is usually straightforward, many diagnostic problems can arise as a result of alterations or absence of its glandular or stromal components. The diagnostic difficulty in such cases can be compounded by tissue that is limited to a small biopsy specimen. The appearance of the glandular component can be altered by hormonal and metaplastic changes, as well as cytologic atypia and hyperplasia. Although the last 2 findings are often referred to collectively as “atypical endometriosis,” they should be separately recognized as their premalignant potential likely differs. In some cases, the endometriotic glands are sparse or even absent (stromal endometriosis). The stromal component can be obscured or effaced by infiltrates of foamy and pigmented histiocytes, fibrosis, elastosis, smooth muscle metaplasia, myxoid change, and decidual change. Occasional findings in endometriosis that may raise concern for a neoplasm include necrotic pseudoxanthomatous nodules, polypoid growth (polypoid endometriosis), bulky disease, and venous, lymphatic, or perineural invasion. Inflammatory and reactive changes within, adjacent to, or at a distance from foci of endometriosis can complicate the histologic findings and include infection within endometriotic cysts, pseudoxanthomatous salpingitis, florid mesothelial hyperplasia, peritoneal inclusion cysts, and Liesegang rings. The histologic diagnosis of endometriosis can also be challenging when it involves an unusual or unexpected site. Five such site-specific problematic areas considered are endometriosis on or near the ovarian surface, superficial cervical endometriosis, vaginal endometriosis, tubal endometriosis, and intestinal endometriosis, including the important distinction of an endometrioid carcinoma arising from colonic endometriosis from a primary colonic adenocarcinoma. Finally, endometriotic foci can occasionally be intimately admixed with another process, such as peritoneal leiomyomatosis or gliomatosis, resulting in a potentially confusing histologic appearance.

Neoplastic and pre-neoplastic changes in gastrointestinal endometriosis: a study of 17 cases.

The clinicopathologic features of neoplasms arising in gastrointestinal endometriosis have not been well characterized. In this series, we report 17 cases of gastrointestinal endometriosis complicated by neoplasms (14 cases) or precancerous changes (three cases). Four patients, one of whom also had hypermenorrhea, presented with chronic abdominal pain and five had obstructive symptoms; one of these also had rectal bleeding. One patient presented with an acute abdomen and fecal peritonitis, one had vaginal bleeding, and one had a progressive change in bowel habits. Nine patients had a long history of endometriosis, 11 patients had had hysterectomies, and eight of these had also received unopposed estrogen therapy. The lesions involved the rectum (6), sigmoid (6), colon, unspecified (2), and small intestine (3), and comprised 8 endometrioid adenocarcinomas (EA), 4 mullerian adenosarcomas (MAS), 1 endometrioid stromal sarcoma (ESS), 1 endometrioid adenofibroma of borderline malignancy (EBA) with carcinoma in situ, 2 atypical hyperplasias (AH), and one endometrioid adenocarcinoma in situ (ACIS). The tumors ranged in size from 2 to 15 cm and all involved the serosa and muscularis propria. Two tumors extended into the mucosa, with mucosal ulceration in one. Follow-up was available in 11 cases. One patient with EA was dead of disease at 1 year, one had two recurrences at 1 and 2 years, and three were alive with no evidence of disease (ANED) at 9 months to 13 years (mean, 68 mos). The patient with the EBA was ANED at 3 months. Two patients with MAS were ANED at 2 and 3 years. The patient with ESS had a recurrence at 3 years and was ANED 6 years after her original diagnosis. One woman with AH was ANED at 60 months and the patient with ACIS was ANED at 16 months. One of the carcinomas was originally misdiagnosed as a primary intestinal adenocarcinoma. The pathologist should be aware of the possibility of a tumor of genital tract type when evaluating intestinal neoplasms in females, particularly if they have a history of endometriosis and have received unopposed estrogen therapy.

Inflammatory pseudotumor of the urinary bladder. A clinicopathological, immunohistochemical, ultrastructural, and flow cytometric study of 13 cases.

We report 13 cases of inflammatory pseudotumor of the urinary bladder in patients having no history of recent local trauma. The average age of the patients (eight females, five males) was 35.4 years (range, 19 to 60 years). Gross hematuria (nine of 13 cases) and recurrent cystitis (three of 13 cases) were the most common presentations. Cystoscopy and gross examination revealed either a polypoid intraluminal mass or a submucosal mural mass, ranging in size from 2 to 7 cm. The lesions were commonly gelatinous. Histological examination showed that the lesions consisted of spindle cells with tapering eosinophilic cytoplasm, typically widely separated in a vascular myxoid matrix with acute and chronic inflammatory cells. In four cases the lesions had more compact cellularity with areas of fibrosis and less myxoid change. The muscularis propria was involved in 10 cases, the perivesical fat in two cases. The spindle cells were immunoreactive for vimentin (10 of 10) and muscle-specific actin (10 of 10). A few cases exhibited immunoreactivity for smoothmuscle- specific actin (three of eight), cytokeratin (two of 10), desmin (two of nine), and epithelial membrane antigen (two of eight). Ultrastructural examination of four cases revealed myofibroblasts, fibroblasts, or a mixture of the two cell types. DNA content analysis by flow cytometry yielded diploid histograms (six of six). Clinical follow-up in all cases demonstrated no evidence of recurrence (mean follow-up, 25.8 months). The findings indicate that this lesion is a benign, likely inflammatory or reparative, mesenchymal lesion that can be recognized by its distinctive pathological features