Epithelioid benign fibrous histiocytoma of skin: clinico‐pathological analysis of 20 cases of a poorly known variant

Abstract

Twenty new cases of epithelioid fibrous histiocytoma, a distinctive but poorly recognized variant of cutaneous benign fibrous histiocytoma are described. Twelve patients were male and eight were female. The age of the patients ranged from 7 to 80 years (median 40 years). Six lesions arose on the lower limb, five on the upper limb, three around the shoulder, two on the abdomen and one each on the eyelid, inner canthus and anal margin. In one case the age and site were not stated. All lesions presented as a solitary, polypoid or slightly raised cutaneous nodule, ranging in size from 0.5 cm to 2 cm in greatest diameter. Follow-up in 14 cases (mean 22.7 months) revealed local recurrence after 42 months in one case. Histologically, the more polypoid tumours were characterized by a n epidermal collarette. In all lesions prominent polygonal or rounded epithelioid cells with abundant eosinophilic cytoplasm, a vesicular nucleus and small eosinophilic nucleoli accounted for at least 50% of the tumour cell population. Individual cells were separated by somewhat hyalinized collagen, containing prominent blood vessels and a sparse mononuclear inflammatory cell infiltrate. The edge of the lesions, especially those that were non-polypoid, often showed more typical features of ordinary fibrous histiocytoma. The main differential diagnosis is with other cutaneous epithelioid neoplasms, especially Spitz naevus.

Variants of dermatofibroma - a histopathological study

“…Clinically, it presents as a polypoid red nodule, generally on the limbs, which is usually confused with pyogenic granuloma. 3,5,11 Histologically, it is characterized as a well-demarcated lesion in the papillary and superficial reticular dermis surrounded by an epidermal collarette. The grenz zone is generally lacking.…”

“…The grenz zone is generally lacking. 5,11 By definition, at least 50% of the lesion is composed of rounded or polygonal epithelioid cells with abundant eosinophilic cytoplasm and round nuclei containing small eosinophilic nucleoli (Figure 3). 3 Mild nuclear pleomorphism and occasional regular mitosis can be found.…”

“…The presence of numerous small vessels located among epithelioid cells is also a common feature. 3,5,11 The most important differential diagnosis is with Spitz nevus.Unlike in Spitz nevus, no junctional component or nesting is present in epithelioidhistiocytoma, and the cells are negative for melanocytic markers, such as S100 protein, melan A and HMB45. 3,5 …”

Epithelioid Cell Histiocytoma with Underlying Artery Damage

“…A suspected case of epithelioid cell histiocytoma with some pericyte differentiation was also reported (11, 12). The frequency of Factor XIIIa labeling in the epithelioid cells of epithelioid cell histiocytomas varies significantly in previous reports from 0% (2), to approximately 50% (1), 50–70% (3), 40–70% (4), and 10–80% (5). In addition, the epithelioid cells of epithelioid cell histiocytomas usually show weak to moderate Factor XIIIa labeling in contrast to the strongly positive dermal dendrocytes scattered in the stroma neighboring the lesions.…”

Lipidized dermatofibromas and their relationship to serum lipids

“…Lipidized dermatofibromas contain scattered cells containing foamy cytoplasm (Figs 1 and 2). They represent only a small fraction of dermatofibromas 6 and have been regarded as an incidental finding with no particular clinical significance. 2 Our study was designed to test this theory.…”