Syringotropic melanoma: a variant of melanoma with prominent involvement of eccrine apparatus and risk of deep dermal invasion

We report 7 cases which can be regarded as a syringotropic melanoma-a unique presentation of melanoma defined as melanoma spreading within the eccrine apparatus into the reticular dermis and/or subcutaneous tissue deeper than any (if present) associated invasive melanoma. Six patients were females, and 1 was a male. Their ages ranged from 32 to 85 years old (average 63). The lesions showed a wide site distribution, occurring on the extremities (4), trunk (2), and head and neck (1). Five melanomas were superficial spreading type; 1 was acral lentiginous type; 1 was unclassified. Four lesions (57%) invaded from within eccrine apparatus at a depth and anatomical level greater than that of an adjacent conventional invasive melanoma arising from the surface epidermis. In 1 lesion, which presented clinically as a pigmented macule, deep dermal syringocentric invasive tumor was the only site of invasion and tumorigenic growth. Thus, this variant of melanoma carries a significant risk of syringocentric deep dermal invasion, which may be unsuspected clinically but must be detected on histological examination to provide the most accurate prognosis and staging information.