Report of an angiosarcoma mimic: cutaneous aneurysmal fibrous histiocytoma.
ABSTRACT Aneurysmal fibrous histiocytoma is an unusual variant of the spectrum of fibrous histiocytomas with the peculiar morphologic appearance of a benign aneurysmal vasoformative process that ultimately culminates in multiple microhemorrhages within the tumor. It looks strikingly different from the usual cutaneous lesions encountered in clinical dermatology practice. A single report of a cutaneous aneurysmal fibrous histiocytoma in the skin of the back of a 60-year-old male is described with emphasis on the immunostaining pattern and review of the literature. There is a significant potential for confusion of this lesion with other cutaneous lesions, clinically as well as pathologically. In our case, the patient presented with a lesion that clinically resembled a hemangioma, was pathologically interpreted initially to be an angiosarcoma, and finally, the revised pathology was interpreted as an aneurysmal variant of a fibrous histiocytoma. Caution is warranted to avoid misinterpretation of cutaneous fibrohistiocytic tumors.
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ABSTRACT: Atypical fibrous histiocytoma is an uncommon, poorly documented variant of cutaneous fibrous histiocytoma. We studied 59 cases of atypical fibrous histiocytoma to better characterize the clinicopathologic spectrum. There were 33 males and 26 females (median age 38 years; range 5-79 years) with solitary lesions arising on lower (25 cases) and upper (17 cases) extremities, trunk (6 cases), head and neck (4 cases), and vulva (1 case); anatomic location was not stated in six cases. Lesions measured 0.4-8 cm in diameter (median 1.5 cm) and clinically were nodules (40 cases), polypoid tumors (18 cases), or a slightly elevated plaque (1 case). Histologically, the lesions were primarily dermal with superficial involvement of the subcutis in one third of the cases. Salient features included a proliferation of pleomorphic, plump, spindle, and/or polyhedral cells with mainly large, hyperchromatic, irregular, or bizarre nuclei, set in a background of classic features of fibrous histiocytoma, including spindle cell areas showing a storiform pattern and entrapped thickened, hyaline collagen bundles, especially at the periphery. Multinucleated giant cells, often with bizarre nuclei and foamy, sometimes hemosiderin-rich, cytoplasm were also variably present. The degree of pleomorphism varied from only focal and minimal (14 cases) or moderate (24 cases) to marked (21 cases). Mitotic activity was observed in 55 lesions, and the number of mitotic figures ranged from 1 to 15 per 10 high power fields. Atypical mitoses were noted in 20 lesions. Furthermore, some cases of atypical fibrous histiocytoma displayed other worrisome features less often observed in ordinary FH, including unusually large size (diameter >2 cm, 8 cases), involvement of the superficial subcutis (19 cases), and geographic necrosis (7 cases). Immunohistochemical studies performed in 42 cases showed only focal smooth muscle actin (10 cases) and CD34 (4 cases) positivity, whereas CD68, S-100 protein, desmin, pan-keratin, and epithelial membrane antigen were negative. Clinical follow-up data available in 21 patients (mean duration of follow-up 50.6 months, median 43 months) revealed local recurrences in three patients (one repeated); two patients developed distant metastases, one of whom died after 96 months. These two cases were not histologically distinct from the group as a whole. We conclude that atypical fibrous histiocytoma has a broader clinicopathologic spectrum than previously realized. Lesions with floridly atypical features represent potential pitfalls for overinterpretation as pleomorphic sarcoma, which would appear to be inappropriate in most cases. Provided that atypical fibrous histiocytoma is treated by complete excision, a benign outcome is to be expected in most cases. However, similar to the cellular and aneurysmal variants of fibrous histiocytoma, atypical fibrous histiocytoma shows a higher tendency to recur locally than ordinary fibrous histiocytoma and may rarely metastasize.American Journal of Surgical Pathology 01/2002; 26(1):35-46. DOI:10.1097/00000478-200201000-00004 · 4.59 Impact Factor
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ABSTRACT: Forty cases of the distinctive but poorly recognized aneurysmal variant of cutaneous fibrous histiocytoma are described. These tumours presented most commonly in middle-age adults, with a slight predilection for females. Anatomical distribution was wide with most cases occurring in the lower limb/limb girdle (50%), upper limb/limb girdle (20%) and trunk (17%). Lesional size ranged from 0.5 cm to 4 cm. Haemorrhage accounted for the rapid clinical growth of some lesions and the frequent clinical confusion with a cyst, a melanocytic lesion or a haemangioma. Five (19%) of the twenty-six cases with follow-up (mean duration 2.5 years) recurred locally, twice in two cases. One of these cases had involvement of a regional lymph node in the second recurrence, most likely as a result of direct local extension. Distinctive histological features were prominent blood-filled spaces, varying from artefact-like clefts to cystic areas mimicking cavernous vascular channels but devoid of an endothelial lining, prominent haemosiderin deposition, numerous siderophages and giant cells, and a moderate mitotic rate. Despite the presence of prominent secondary changes due to haemorrhage, all cases showed cellular polymorphism, hyalinized collagen bundles surrounded by tumour cells in the periphery of the lesion and 88% showed some degree of epidermal hyperplasia, as seen in common fibrous histiocytoma. Immunohistochemistry (ABC method) revealed only vimentin and, rarely, focal smooth muscle actin positivity. CD68 was positive in some reactive macrophages only. Stains for CD31, CD34, desmin and factor XIIIa were negative in all cases tested.(ABSTRACT TRUNCATED AT 250 WORDS)Histopathology 05/1995; 26(4):323-31. DOI:10.1111/j.1365-2559.1995.tb00193.x · 3.30 Impact Factor
Article: Angiosarcomas of the skin.[Show abstract] [Hide abstract]
ABSTRACT: Angiosarcomas of the skin develop almost exclusively in the following clinical settings: (1) the lymphedematous extremity, secondary to prior mastectomy in most instances; (2) the face and scalp, usually in elderly individuals; and (3) skin that has been previously radiated. Microscopically, there is a spectrum of architectural patterns. The best differentiated tumors exhibit obvious vascular spaces, which are lined by variably atypical endothelial cells, and that characteristically dissect between fibers of the reticular dermis. With proliferation of the atypical endothelial calls, vasoformative features are less evident, and there is often a syncytium of cellular bands composed of fusiform or spindled cells or, less commonly, cords, nests, and nodules of distinctly epithelioid cells. Overgrowth of the cellular elements can create seemingly patternless sheets of tumor. The foregoing architectural spectrum may be displayed in its entirety within a single biopsy specimen, and a multifocal distribution within the dermis is characteristic. Cytologic pleomorphism and mitotic figures are often obvious, but both criteria of malignancy may be essentially absent in the best differentiated fields. Ultrastructural observations consistently show differentiation toward endothelial cells and, in many cases, findings consistent with differentiation toward blood vessels. Both factor VIII-related antigen and Ulex europaeus lectin are reliable immunohistochemical markers. The outlook for patients with cutaneous angiosarcoma is poor, with a median survival of 20 months and a 5-year survival of 15%.Seminars in Diagnostic Pathology 03/1987; 4(1):2-17. · 1.80 Impact Factor