A typical case of infantile haemangioma mixed with dermal melanocytosis on back

Infantile haemangioma (IH) is a most common type of benign vascular tumor of infancy. IH exhibit a characteristic life cycle – proliferation and
involution phase. In proliferation phase, pallor, telangiectasias, or duskiness is characteristic. Dermal melanocytosis are peculiar melanocytic lesions
characterized by a bluish discoloration of large portions of the skin. A 4-year-old boy presented with solitary, 7cm sized, mixed elevated plaque with
half pink and half blue coloration on the back since 50 days of age. The lesion slowly increased in size by time. On the histopathology examination,
pinkish part showed mildly proliferative spindle cells in dermis with mildly increased dermal vessels, and bluish part showed proliferating spindle
cellular lesion with scattered dermal melanophages. In the immunohistochemical analysis, CD34 was strongly positive at pinkish part. Fontana-
Masson stain was positive for the pigmented cells in deep dermis and S-100 was negative at bluish part. In ultrasonography of pinkish part,
heterogeneous enhancement was observed at subcutaneous lesion, suggestive of haemangioma. No abnormal feature was found at bluish part.
Based on these features, IH and dermal melanocytosis was diagnosed. Considering pathogenesis of IH and dermal melanocytosis, each parts
originated from two different disease and locate next to each other by chance. Thus, we introduce this as a rare case of IH and dermal melanocytosis
on the back.