Atrophic dermatofibroma accompanied by aneurysmatic characteristics

A 40-year-old man presented a painful haemorrhagic plaque on his chest in the same location where a nodular lesion had been presented for many years. After 2 months, the plaque was replaced by a depressed lesion. The lesion diagnosed as an anetoderma was excised and the biopsy showed an atrophic dermatofibroma accompanied by aneurysmatic characteristics.     

Atrophic variants of dermatofibroma and dermatofibrosarcoma protuberans

Dermal atrophy of more than 50% of the locoregional dermis may be the predominant histopathological feature in dermatofibroma and dermatofibrosarcoma protuberans. This may cause diagnostic difficulties. In the present study 26 cases of atrophic dermatofibroma were compared with three cases of atrophic dermatofibrosarcoma protuberans. Clinically, both conditions mostly occurred on the (upper) trunk of females. While atrophic dermatofibroma usually presented as a reddish, umbilicated lesion (0.5–1-cm), often suspected to be a basal cell carcinoma, atrophic dermatofibrosarcoma protuberans showed irregularly arranged tan-brown plaques (3–6 cm). Histologically, atrophic dermatofibroma showed a regular silhouette with a smooth nodular (9/26) or scalloped lower margin with an intervening lace-like pattern of superficial fatty tissue infiltration (17/26) and variable sclerosis; atrophic dermatofibrosarcoma protuberans showed a deep, irregular infiltration of fatty tissue in a lacelike/honeycomb and/ or multilayered pattern, but no sclerosis. Immunohistochemically, atrophic dermatofibroma was mostly negative with QBEnd 10 (CD34; 24/26), variably positive for factor XIIIa (20/26) and metallothionein (11/26). Labelling for factor XIIIa and metallothionein was usually seen in 'early' (metabolically active) lesions, while 'late' sclerotic ones were negative. In contrast to atrophic dermatofibroma all three atrophic dermatofibrosarcoma protuberans showed a consistently uniform profile: CD34 positive, factor XIIIa and metallothionein negative. Our study delineates atrophic dermatofibroma and atrophic dermatofibrosarcoma protuberans as distinct entities clearly distinguishable from each other by clinicopathologic criteria.     

Palisading subcutaneous fibrous histiocytoma

A case of palisading subcutaneous fibrous histiocytoma, a very rare variant of fibrous histiocytoma (dermatofibroma), arising in the wrist of a 41-year-old man is presented. An unencapsulated subcutaneous tumor measuring 0.8 x 0.8 x 0.7 cm was histologically characterized by predominant nuclear palisading and a peripheral area with a pattern quite characteristic of conventional fibrous histiocytoma. Immunohistochemically, the tumor cells were strongly positive for vimentin, alpha-smooth muscle, and muscle actin, but negative for S-100 protein, indicating a fibroblastic or myofibroblastic nature. The patient has been well without recurrence for 6 years and 8 months after the excision. This neoplasm should be differentiated from benign and malignant skin or soft tissue tumors with a palisading pattern. Pathologists and clinicians should know of the existence of this type of fibrous histiocytoma and should avoid overdiagnosis and overtreatment.     

Innovative combined therapy for multiple keloidal dermatofibromas of the chest wall: A novel case report

Dermatofibromas are benign soft tissue tumors that predominantly affect the limbs, and more rarely the chest. Keloidal dermatofibroma is a rare subtype with distinct clinicopathological features and an aggressive clinical course. By researching the evolution of the disease in this study, we aimed to summarize our experience of managing a rare patient who underwent five surgeries for keloidal dermatofibroma that developed sequentially in the upper arm and chest and propose a novel treatment for keloidal dermatofibroma. We concluded that keloidal dermatofibroma involving larger areas, high tension sites, and multiple localizations can be treated using the principles of pathological scar management.     

Atypical fibrous histiocytoma of the scrotum

Atypical fibrous histiocytoma is a rare neoplasm. A scrotal location for this tumor is even more unusual. We report a case of a 90-year-old man with scrotal atypical fibrous histiocytoma. Our case had histologic features consistent with those cases previously reported in the literature. The tumor consists of cells with large hyperchromatic irregular nuclei, bizarre multinucleated cells (monster cells), and xanthomatous cells with large prominent nuclei set in a background of classic fibrous histiocytoma. Rare mitotic figures are identified. Immunohistochemical studies showed the tumor cells to be positive for vimentin, smooth muscle actin, desmin, KP-1, factor XIIIa, and MIB-1 (less than 10%). In addition to the expected immunohistochemical studies, the tumor stained diffusely positive for CD117. To our knowledge, this is the first report of atypical fibrous histiocytoma of the scrotum.     

Congenital multiple clustered dermatofibroma

Multiple clustered dermatofibroma (MCD) is a rare tumour which usually appears during the first and second decades of life. We report a man in whom the MCD was congenital, although during the first few years of his second decade it extended to involve a broad zone on the left hip, gluteal region and upper thigh.     

Clear cell dermatofibroma

This series presents six cases of a rare variant of dermatofibroma, characterized by marked clear cell change. All lesions occurred on the lower extremities of middle-aged adults (four women, two men), mostly with the clinical diagnosis of fibrohistiocytic lesion. Histological examination revealed well circumscribed, faintly stained dermal to subcutaneous lesions which were due to the overwhelming presence of clear cells (<90%), some with prominent PAS-positive cytoplasmic granulation. Overlying epidermal hyperplasia as well as storiform arrangement of spindle cells, sclerotic collagen and some interspersed lympho-histiocytic infiltrate at the periphery of the lesion indicated the fibrohistiocytic origin. Individual histopathological peculiarities included : bizarre giant cells in two cases, prominent perivascular lympho-histiocytic response, perifollicular arrangement and haemangiopericytoma-like features with iron deposition in one case each. Immunohistochemically three of four lesions showed moderate reactivity for factor XIIIa and two of four with an anti-metallothionen marker E9, but were otherwise negative with a broad panel of markers. Electronmicroscopy in two cases revealed large pools of glycogen beside focal, prominent endoplasmic reticulum and lysosomes in some granular cells, but only optically translucent cells in cases of clear cells. Recognition of clear cell dermatofibroma is important as the differential diagnosis includes some entities with more serious outcome/considerations such as metastases of renal cell carcinoma, xanthogranulomatous reactions, balloon cell naevus/melanoma and clear cell sarcoma.     

Clear cell dermatofibroma

This series presents six cases of a rare variant of dermatofibroma, characterized by marked clear cell change. All lesions occurred on the lower extremities of middle-aged adults (four women, two men), mostly with the clinical diagnosis of fibrohistiocytic lesion. Histological examination revealed well circumscribed, faintly stained dermal to subcutaneous lesions which were due to the overwhelming presence of clear cells (<90%), some with prominent PAS-positive cytoplasmic granulation. Overlying epidermal hyperplasia as well as storiform arrangement of spindle cells, sclerotic collagen and some interspersed lympho-histiocytic infiltrate at the periphery of the lesion indicated the fibrohistiocytic origin. Individual histopathological peculiarities included : bizarre giant cells in two cases, prominent perivascular lympho-histiocytic response, perifollicular arrangement and haemangiopericytoma-like features with iron deposition in one case each. Immunohistochemically three of four lesions showed moderate reactivity for factor XIIIa and two of four with an anti-metallothionen marker E9, but were otherwise negative with a broad panel of markers. Electronmicroscopy in two cases revealed large pools of glycogen beside focal, prominent endoplasmic reticulum and lysosomes in some granular cells, but only optically translucent cells in cases of clear cells. Recognition of clear cell dermatofibroma is important as the differential diagnosis includes some entities with more serious outcome/considerations such as metastases of renal cell carcinoma, xanthogranulomatous reactions, balloon cell naevus/melanoma and clear cell sarcoma.