Glomus Tumor Arising in a Mature Teratoma of the Ovary.
The glomus tumor is an uncommon, benign soft tissue neoplasm thought to arise from neuromuscular cells of the glomus apparatus, a specialized arteriovenous anastomosis. The latter is found most often in the deep dermis of the extremities, where it has a role in thermal regulation. Although glomus tumors occur most frequently at these same sites, they are occasionally found in anatomic locations not typically associated with glomera, such as in the gastrointestinal, respiratory, and female genital tracts.[1,2] In the female reproductive tract, glomus tumors have been described in the external genitalia,[3-6] vagina[7,8] uterine cervix, and myometrium. To our knowledge, glomus tumors occurring in the ovary have not been reported previously. The case presented here is of particular interest because the glomus tumor was initially interpreted as an ovarian metastasis from the patient's previously diagnosed squamous carcinoma of the cervix, which was locally recurrent in the vagina.
REPORT OF A CASE
A 43-year-old woman with an unremarkable past medical history presented with an abnormal cervicovaginal (Papanicolaou) smear and underwent colposcopy and cervical biopsy. The latter showed high-grade squamous intraepithelial lesion with focal areas suspicious for invasion. She was treated with a cervical cone biopsy and subsequent hysterectomy, revealing residual high-grade squamous intraepithelial lesion with foci suspicious for, but not diagnostic of invasion.
Approximately 1 year later, the patient developed vaginal recurrence, and vaginal biopsy documented minimally invasive squamous carcinoma. She underwent partial vaginectomy, pelvic node dissection, and concurrent bilateral salpingo-oophorectomy. The parametrium, pelvic lymph nodes, left adnexa, and peritoneal washings were negative for carcinoma.
The right ovary contained an incidental 0.8-cm nodular lesion, initially interpreted as metastatic squamous carcinoma. Because of the rarity of what appeared to be an isolated ovarian metastasis from the vaginal neoplasm, the pathologic material was sent to the Armed Forces Institute of Pathology, Washington, DC, for consultation.
Hematoxylin-eosin-stained slides from the cervical, vaginal, and ovarian lesions were reviewed. Additional tissue sections from the right ovary were stained with pan-cytokeratin (AE1/3, CK1) (1:400 dilution, Dako Corporation, Carpinteria, Calif; Boehringer-Mannheim, Indianapolis, Ind), CAM 5.2 (1:200, Becton Dickinson, San Jose, Calif), epithelial membrane antigen (1:200, Dako), chromogranin (1:1600, Boehringer-Mannheim), factor VIII-related antigen (1:1600, Dako), smooth muscle actin (1:800, Sigma Chemical Co, St Louis, Mo), desmin (clone DER-11) (prediluted, Ventana Medical Systems Inc, Tucson, Ariz), and glial fibrillary acidic protein (1:800, Dako), using the avidin-biotin-peroxidase complex method.
For ultrastructural analysis, a representative portion of the ovarian neoplasm was obtained from a paraffin block of formalin-fixed tissue. The tissue sample was extracted with xylene, rehydrated, and refixed in 2% glutaraldehyde overnight. It was then postfixed in 1% buffered osmium tetroxide and embedded in epoxy resin following dehydration in graded alcohols and passage through propylene oxide. Ultrathin tissue sections were stained with uranyl acetate and lead citrate, and examined in a Zeiss (Leo Electron Microscopy, Thornwood, NY) 109 transmission electron microscope.
A moderately to poorly differentiated, nonkeratinizing, minimally invasive squamous carcinoma was present in the vaginal biopsy and vaginectomy specimens. Superficially, the tumor assumed a papillary configuration. The carcinoma consisted of nests of tumor composed of a relatively monomorphic cell population with round nuclei, evenly distributed chromatin, and scanty cytoplasm (Figure 1). Mitotic figures and individual cell necrosis were readily apparent.
[Figure 1 ILLUSTRATION OMITTED]
The right ovary measured 4 x 2 x 1.5 cm and contained a solitary, firm, 0.8-cm nodule located just beneath the cortical surface. The ovarian neoplasm appeared discrete at low-power microscopic examination, although the individual nests of tumor had a pseudoinfiltrative appearance (Figure 2). Morphologically, the solid nests of tumor were composed of monotonous, round, cytologically bland epithelioid cells with scanty cytoplasm, imparting some resemblance to the vaginal carcinoma. However, no mitotic activity was appreciated, and close scrutiny revealed occasional central capillary blood vessels within the nests (Figure 3). This constellation of features is characteristic of glomus tumors arising in the dermis of the extremities. Scattered collections of fat cells within the intercellular stroma provided a clue to the teratomatous nature of this lesion. Moreover, the well-demarcated cellular nodules were separated by fibrillar hypocellular stroma that was immunoreactive with glial fibrillary acidic protein, consistent with glial tissue. No other teratomatous components were identified. These findings are consistent with the interpretation of a glomus tumor arising in a mature teraroma.
[Figures 2-3 ILLUSTRATION OMITTED]
The ovarian tumor was immunoreactive for smooth muscle actin (Figure 3, inset) and lacked reactivity for desmin, chromogranin, factor VIII-related antigen, and a panel of epithelial markers (pan-cytokeratin, CAM 5.2, and epithelial membrane antigen), compatible with the diagnosis of glomus tumor. This immunoprofile is similar to that described by others for glomus tumors.[12,13]
Ultrastructural examination revealed relatively uniform cells surrounded by a continuous basal lamina with round to ovoid nuclei, small nucleoli, and a paucity of cytoplasmic organelles. The cytoplasm was rich in mitochondria and free ribosomes, and contained scattered arrays of thin filaments with focal dense bodies. Numerous pinocytotic vesicles were present, aligned in a layer subjacent to the plasma membrane (Figure 4). No cell junctions or neurosecretory granules were identified. These ultrastructural features closely resemble those of smooth muscle cells and are characteristic of glomus tumors.
[Figure 4 ILLUSTRATION OMITTED]
Glomus tumors arising in the female genital tract are rare. A total of 10 cases have been reported in the English literature, mostly as isolated case reports. Reported sites of involvement include the vulva,[4-6] clitoris,[3,6] vagina,[7,8] cervix, and myometrium. These glomus tumors occurred in women with a mean age of 41.9 years (range, 27-53 years) and ranged in size from 0.4 to 5.0 cm (mean, 1.5 cm). Seventy percent were 1.0 cm or smaller, and all were well circumscribed. The patient with the 5-cm vaginal tumor presented with heavy vaginal bleeding. Only the vulvar and clitoral lesions were described as painful; most of the other glomus tumors were incidental microscopic findings at the time of hysterectomy for benign disease. Clinical follow-up was available in 5 (50%) cases. Four patients were symptom-free and without recurrence 3 to 12 months after diagnosis. One patient with a 3-cm glomus tumor involving the periurethral area of the vulva, clinically thought to represent a Skene's gland abscess, had residual tumor removed 10 months after diagnosis and was subsequently disease-free for more than 10 years.
To our knowledge, there have been no prior reports of a glomus tumor arising in the ovary either de novo or in association with a teratoma. Moreover, we are unaware of any descriptions of a glomus tumor arising in a teratoma at any other anatomic site. The glomus tumor described in this report was morphologically indistinguishable from glomus tumors that typically arise in the extremities, and showed similar immunohistochemical and ultrastructural features. In their usual location, glomus tumors are generally diagnosed without difficulty, given their distinctive clinical presentation and morphology. However, when a glomus tumor occurs in an unusual site, particularly in a patient with a primary neoplasm elsewhere (as in the case described here), other lesions must be considered in the differential diagnosis.
Metastatic squamous carcinoma to the ovary is exceedingly rare, accounting for only 2.5% of ovarian metastases in one series. Moreover, Toki et al found ovarian metastases in only 1 (0.19%) of 524 cervical squamous carcinomas of FIGO stage IB or greater; interestingly, the metastatic focus was microscopic in size. Although our case was initially interpreted as a microscopic ovarian metastasis, subtle morphologic clues suggested that the carcinoma in the vagina and the ovarian tumor represented different entities. First, the ovarian lesion lacked the prominent mitotic activity of the vaginal recurrence. Second, the ovarian neoplasm contained central capillary blood vessels within rare nests of tumor. Finally, scattered collections of fat cells within the tumoral stroma suggested the possibility of a teratoma.
In addition to metastatic squamous carcinoma, the differential diagnosis includes a number of primary neoplasms arising in a teratoma. These include nonkeratinizing squamous carcinoma, cutaneous adnexal tumor, carcinoid tumor, melanocytic neoplasms, epithelioid leiomyoma, and hemangiopericytoma. In general a panel of immunohistochemical stains should prove useful, when necessary, in excluding these diagnostic possibilities. Glomus tumors are invariably nonreactive with antibodies to cytokeratin, neuroendocrine markers, and melanoma-specific antigen (HMB-45), and are intensely reactive with smooth muscle actin antibody.[2,13] S100 protein expression is rarely present in glomus tumors.[2,13] Although a subset of glomus tumors stain positively for desmin, the staining in leiomyomas is typically stronger and more diffuse than that described for glomus tumors.
In summary we describe a glomus tumor reflecting almost a monodermal ovarian teratoma that proved diagnostically challenging, owing to both its highly unusual location and morphologic resemblance to the patient's recurrent cervical carcinoma.
Accepted for publication January 25, 2000.
From the Department of Gynecologic and Breast Pathology, Armed Forces Institute of Pathology, Washington, DC. Dr Silver is currently affiliated with the Department of Pathology, Magee Womens Hospital, Pittsburgh, Pa.
The opinions and assertions contained herein are the private views of the authors and are not to be construed as official or as representing the views of the United States Department of the Army or the Department of Defense.
Reprints: Susan A. Silver, MD, Department of Pathology, Magee Womens Hospital, 300 Halket St, Pittsburgh, PA 15213.
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|Author:||Silver, Susan A.; Tavassoli, Fattaneh A.|
|Publication:||Archives of Pathology & Laboratory Medicine|
|Date:||Sep 1, 2000|
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