A “Yellow Submarine” in dermoscopy

BACKGROUND: Histiocytic sarcoma (HS) is an extremely rare, non-Langerhans cell tumor. HS affects especially adults, its etiology is unknown yet. Skin could be interested by papules or nodules, single or multiple. CASE REPORT: A Caucasian man in his late 40s came to our clinic for a naevi evaluation. During the visit, a rose papulonodular lesion was observed in the lumbar region. This lesion was completely asymptomatic, and it had been there for an indefinite period. The clinical evaluation revealed that the lesion appeared elevated, of 9 x 15 mm in dimension, symmetrical and of a homogeneous pinkish colour. The videodermoscopical evaluation revealed a homogeneous yellow central pattern, polymorphic vessels, an eccentric peripheral pigmentation and a white collar. An excisional biopsy was performed. The morphology and the expression of CD163, CD68 and/or lysozyme to the immunophenotypic analysis, revealed the true nature of the lesion. CONCLUSION: HS is usually diagnosed at an already advanced clinical stage and it has a high mortality rate even today. Dermoscopy, showing a yellow and distributed homogeneously colour, can facilitate its hard diagnosis