Ulcerated Storiform Collagenoma

This rare form of benign fibrous tumor can be associated with Cowden's disease. An important differential diagnosis of any fibromatous lesion showing a whorled storiform architecture with neutrophils would be a chronic leukocytoclastic vasculitis, namely erythema elevatum diutinum. One must also be cognizant of a sclerosing perineurioma.

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Slide 1: 58 year-old man with a hip lesion. The bisected specimen shows a dermal based proliferation with attendant ulceration.

Slide 2: There is a very distinct fibromatous lesion characterized by a whorled pattern of laminated fibroplasia with prominent clefting.

Slide 3: The nuclei are small and hyperchromatic. There are thick brightly eosinophilic bands of collagen.

Slide 4: There is some focal staining for epithelial membrane antigen.

Slide 5: There is extensive immunoreactivity for CD34.

Slide 6: A few dendritic cells are highlighted by Factor-XIIIA. Overall the diagnostic assessment in this case is that of a storiform collagenoma. While there is some focal staining for epithelial membrane antigen, the lack of greater staining along with the extent of staining for CD34 does not support a diagnosis of perineureoma.