Pyogenic Granuloma-Like Kaposi Sarcoma: A Diagnostic Challenge

An 81-year-old woman presented with a 2-month history of a painless nodule on the left foot that bled easily after minor trauma. She had no medical history and did not report any preexisting lesion. Physical examination revealed a 2 cm × 3 cm, exophytic and reddish-colored nodule, with an ulcerated and soft surface (Figure 1). There were no other skin lesions or abnormal physical findings. The diagnosis of a pyogenic granuloma (PG) was suggested. A biopsy specimen was obtained from the center of the lesion and stained with hematoxylin and eosin. Histopathologic examination revealed a marked proliferation of both capillary cells and spindle-shaped cells separated by slit-like vessels containing multiple erythrocytes (Figure 2A). Immunochemical analysis showed positivity for CD34 and human herpes virus (HHV)-8 in both endothelial and spindle cells (Figure 2B). Perls' staining showed abundant hemosiderin deposits in the tumor stroma (Figure 2C). These findings were consistent with the diagnosis of Kaposi sarcoma (KS). Laboratory tests eliminated a human immunodeficiency virus (HIV) infection, and no metastatic lesions were found on radiologic examinations. The lesion was treated with laser excision, with no recurrence at the 2-year follow-up.