There is a histopathological similarity between cutaneous apocrine carcinoma (CAC) and breast carcinoma. Cutaneous histiocytoid or signet-ring cell (SRC) carcinoma is a rare neoplasm, which usually occurs on the eyelid, and less commonly on the axilla. The precise histogenesis of this carcinoma remains controversial. We report the case of a man with a cutaneous histiocytoid SRC carcinoma of the axilla having histopathological and immunohistochemical features that were quite similar to histiocytoid lobular carcinoma (histiocytoid LC) of the breast, which is a subtype of classic invasive lobular carcinoma of the breast with apocrine differentiation. We consider this case to be a type of CAC equivalent to histiocytoid LC of the breast, based on the features and the occurrence on the axilla. The patient was treated with adjuvant chemotherapy according to the general guidelines for the treatment of breast carcinoma.

Palisaded neutrophilic granulomatous dermatitis (PNGD) is a rare dermatologic condition which shows various clinical and histopathological features. Although the PNGD lesions have been suggested to begin as leukocytoclastic vasculitis (LCV), there is still insufficient clinicopathological information in the reported cases of PNGD in acute stage with LCV. The relationship between PNGD and interstitial granumatous dermatis (IGD) also remains unclear. This report presents the case of a 60-year-old female patient with multiple erythematous nodules on the extremities. She had no underlying systemic disease detected to date, although transient, abnormal liver function tests were seen. The histopathological examination of an erythematous nodule revealed the features of PNGD in the acute stage. The patient presented the characteristic features of LCV including palisaded granulomatous pattern, and the interstitial granulomatous pattern was seen together, suggesting that PNGD with LCV can show an interstitial granulomatous pattern. The present case also suggested that PNGD in the acute stage with LCV tends to clinically manifest as erythematous nodules on the extremities and histopathologically shows a remarkable papillary edema and an extensive fibrin deposition in and around the vessel wall. PNGD may be associated with transient liver dysfunction.

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