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Partial monosomy 13q, a chromosomal alteration originally reported in spindle cell lipoma, has also been documented in a few cases of mammary myofibroblastoma. Subsequently, a monoallelic loss of RB1 and FOXO1, located on 13q14, was identified in some cases of cellular angiofibroma, a benign stromal tumor of the lower female genital tract. This cytogenetic finding and the overlapping morphologic and immunohistochemical features shared by spindle cell lipoma, mammary myofibroblastoma, and cellular angiofibroma strongly suggest a histogenetic link among these tumors. Recently, we have emphasized morphologic and immunohistochemical similarities between mammary and vulvovaginal myofibroblastoma. The aim of the present study was to asses if these 2 tumors share the same chromosomal alteration. We studied the chromosome 13q14 region by fluorescence in situ hybridization analysis in a series of mammary and vaginal myofibroblastomas, with a readable signal in 7 of 13 mammary myofibroblastomas and 5 of 7 cases of vaginal myofibroblastomas. Despite histologic variation, most of the mammary (5/7) and vaginal (3/5) myofibroblastomas showed monoallelic deletion of FOXO1 in more than 22% of the cell populations. Our findings confirm that mammary myofibroblastoma is a tumor that exhibits chromosome abnormalities associated with the loss of the 13q14 region. In addition, we show for the first time that myofibroblastoma of the lower female genital tract also exhibits the same chromosomal abnormality, supporting the hypothesis that both tumors are in the spectrum of a single entity, likely arising from a common precursor cell., (Copyright © 2012 Elsevier Inc. All rights reserved.)

To date, only a few cases of "rosette forming t(6;11), HMB45-positive renal carcinoma" have been published. In this article, we contribute further data on 4 cases of this rare entity. Patients were 3 women and 1 man with an age range of 20 to 54 years (median, 23 years). Follow-up (range, 3-5 years; median, 4 years) did not reveal any metastatic events or recurrences. All tumors were well circumscribed and mostly encapsulated with homogeneous gray to tan cut surfaces. No necrosis was seen. All tumors displayed a solid or solid/alveolar architecture and contained occasionally long and branching tubular structures composed of discohesive neoplastic cells and pseudorosettes. The presence of pseudorosettes was a constant finding, but the number of pseudorosettes varied significantly among cases. All cases displayed focal immunoreactivity for the melanocytic marker HMB45, cathepsin K, and vimentin. Melan A, tyrosinase, cytokeratins, CD10, and microphthalmia transcription factor were each positive in 3 of 4 cases. On ultrastructural examination, numerous electron-dense secretory cytoplasmic granules with some resemblance to melanosomes were identified. The pseudorosettes were composed of reduplicated basement membrane material surrounded by small lymphocyte-like neoplastic cells. Using reverse transcription polymerase chain reaction, 2 tumors were positive for the Alpha-TFEB fusion transcript. The presence of the translocation t(6;11)(Alpha-TFEB) was confirmed in 2 analyzed cases. No von Hippel-Lindau tumor suppressor gene mutation, promotor methylation or loss of heterozygosity of 3p was found. Losses of part of chromosome 1 and chromosome 22 were found in one case., (Copyright © 2012 Elsevier Inc. All rights reserved.)

We analyzed the clinicopathologic features of 10 cases of vulvovaginal myofibroblastoma to widen its morphological and immunohistochemical spectrum. Most tumors (8/10 cases) were located in the vagina. The patients' age ranged from 44 to 77 years, and tumor size ranged from 0.4 to 3 cm. Histologically, 5 tumors had the characteristics of vulvovaginal myofibroblastoma. In addition, we identified 3 cases composed of spindle-shaped cells arranged in short fascicles with intervening thick collagen bands, closely reminiscent of mammary myofibroblastoma. Notably, 1 case resembled Sertoli cell tumor, sclerosing type, because of its predominant cord-like arrangement. In another case, there were highly cellular areas composed of uniform-packed, rounded cells that, at low magnification, looked like a malignant "small round blue cell tumor." A variably thick band of native connective tissue separated tumors from the overlying squamous epithelium even if, in 3 cases, tumor cells extended up to the epithelium. In 7 cases, a variable number of vessels showed perivascular hyalinization. Only rare mitotic figures were identified. All tumors were diffusely positive for vimentin, desmin, and CD99. A variable staining intensity was observed for CD34, Bcl-2, B-cell lymphoma 2 (Bcl-2) CD10, estrogen receptor, and progesterone receptor in most cases, but none expressed α-smooth muscle actin. We emphasize that vulvovaginal myofibroblastoma encompasses a morphological spectrum wider than previously described. The overlapping morphological and immunohistochemical features of vulvovaginal and mammary myofibroblastomas led us to speculate that these are related entities with morphological variations on a common basic theme likely dependent on anatomical location., (Copyright © 2012 Elsevier Inc. All rights reserved.)