Mammary-type myofibroblastoma (MFB) is a rare, benign spindle cell neoplasm occurring along the milkline, with extension from the mid-axilla to the medial groin. It is histologically and immunohistochemically identical to MFB of the breast and is part of a spectrum of lesions that includes spindle cell lipoma and cellular angiofibroma. Recently, we experienced two cases of mammary-type MFB involving male patients aged 30 and 58 years, respectively. The tumors were located in the right scrotal sac and in the right axilla. Wide excisions were performed. Microscopically, the masses were composed of haphazardly arranged, variably sized fascicles of bland spindle cells and were admixed with mature fat tissue. The spindle cells in both cases showed immunopositivity for desmin and CD34 and negativity for smooth muscle actin. Loss of retinoblastoma (RB)/13q14 loci is a characteristic genetic alteration of mammary-type MFB, and we identified loss of RB protein expression by immunohistochemical staining. We emphasize the importance of awareness of this rare neoplasm when a spindle cell neoplasm is accompanied by desmin immunopositivity. The second patient was alive without recurrence for 20 months, and the first patient had not been followed.
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Intranodal palisaded myofibroblastoma is a rare benign mesenchymal neoplasm of the lymph node. It is characterized by intranodal spindle cell proliferation along with amianthoid fibers and prominent hemorrhage. It has been rarely reported in South Korea. We report here on a case of palisaded myofibroblastoma that arose in the left inguinal lymph node. The tumor mass was well demarcated, and it was composed of a proliferation of benign-looking spindle cells.
It showed focal hemorrhage and a fibrous pseudocapsule. The tumor cells displayed little pleomorphism, no mitotic count, and characteristic palisading nuclei and amianthoid fibers.
The tumor cells were positive for smooth muscle actin, vimentin, and also for desmin, but they were negative for S-100 protein, supporting the diagnosis of myofibroblastoma.
Angiomyofibroblastoma of the vulva is a rare mesenchymal tumor. It has been diagnostically confused with aggressive angiomyxoma which has a somewhat different clinical course and therapy. Herein we report a case of angiomyofibroblastoma of the vulva in a 46-year-old female.
Microscopically, there were alternating hypercellular and hypocelluar edematous zones in which abundant capillary blood vessels were irregularly distributed. Spindle, plump spindle, and oval stromal cells were concentrated around the blood vessels, or loosely dispersed in the hypocellular area. Immunohistochemically, the stromal cells were positive for desmin, vimentin, muscle-specific actin and weakly positive for S-100 protein. Ultrastructural studies showed well developed rough endoplasmic reticulum, abundant intermediate filaments, and pinocytic vesicles in the stromal cells.
Angiomyofibroblastoma is a distinctive, hitherto uncharacterized, benign soft tissue tumor of the vulva with histology similar to an aggressive pelvic angiomyxoma. It can be distinguished from an aggressive angiomyxoma by its circumscribed borders, higher cellularity, more numerous blood vessels, the frequent presence of plump stromal cells, minimal stromal mucin, and rarity of erythrocyte extravasation. We experienced a case of angiomyofibroblastoma of the vulva occurring in a 45-year-old woman. The lesion was a well-defined but not encapsulated mass, 4.5x4.2 cm. Histologically the mass was characterized by alternating hypercellular and hypocellular edematous zones in which abundant blood vessels were irregularly distributed. Immunohistochemically, the spindled, plump spindled, and oval stromal cells were reactive for vimentin and desmin, but not for cytokeratin, or S-100 protein.
A case of myofibroblastoma of the breast in a 55-year-old man is described. Myofibroblastoma is a relatively recently recognized benign stromal tumor, and predominantly occurs in middle aged men. The pateint presented with a nontender firm mass in his right breast. Fine needle aspiration biopsy revealed bland looking stromal cell clusters without epithelial cells. Simple excision was done and the patient discharged uneventfully. The mass was well demarcated, lobulated and sligtly myxoid. Microscopically bipolar elongated spindle cell fascicles with interspersing broad collagen bands are so characteristic. Ultrastructurally the tumor cell show features of fibroblast as well as smooth muscle cell.
Angiomyofibroblastoma is a rare, benign mesenchymal tumor of the vulva. Since it was described in 1992 by Fletcher, 15 cases have been reported in literature. We recently experienced a recurred angiomyofibroblastoma of the vulva.
A 45-year-old woman was presented initially in 1991 with a mass of labium major and local excision of tumor mass had been performed. A histologic diagnosis was made of angiomyxoma, but this diagnosis was revised to angiomyofibroblastoma by the authors. The recurred mass was well circumscribed, measuring 2.5x1.6x1.5cm in dimensions.
Microscopically the tumor was characterized by high cellularity, numerous blood vessels(which lack prominent hyalinization), and plump stromal cells.
Immunohistochemically, the stromal cells were reactive for vimentin and desmin, but not alpha-smooth muscle actin, or S-100 protein. We thought that this case was a recurred angiomyofibrblastoma of the vulva due to incomplete surgical excision.
Mammary-type myofibroblastoma of the soft tissue is a benign mesenchymal tumor, and it is a recently established clinical entity. We report a case of myofibroblastoma of the chest wall with a prominent epithelioid feature, that occurred in a 12-year old female. Although the lesion occurred in the breast area, there was no breast parenchyma in or around the mass, which favored soft tissue of the chest wall origin.
The tumor was immunohistochemically identical to the mammary-type myofibroblastoma with diffuse and strong positivity against CD34 and desmin. The myoepithelial differentiation of the tumor was further supported by the electron microscopic analysis. This case indicates that mammary-type myofibroblastoma can occur in a young girl. The mammary-type myofibroblastoma should be considered a differential diagnosis, among epithelioid soft tissue neoplasms in the chest wall when the proper immunohistochemical work-up is done.