What is a key characteristic of melanomas?

A key characteristic of melanomas is the presence of prominent dark black granules, which are melanin-producing pigments. These granules indicate the tumor's melanocytic origin and are indicative of the neoplastic transformation of melanocytes. In melanomas, the abnormal proliferation of these pigment-producing cells results in an accumulation of melanin, which can appear as dark granules within the tumor cells or in the surrounding tissue.

The prominence of these granules can often help in the histological identification of melanoma in cytology samples, aiding in distinguishing it from other types of skin lesions or tumors. Recognizing these granules is essential for accurate diagnosis, as they can provide significant insight into the behavior and origin of the tumor.

Contextually, other characteristics associated with different tumor types include eccentrically located nuclei, which may be found in various malignancies but is not specific to melanoma. Exfoliation in sheets generally pertains to certain types of carcinomas, and round cell morphology is typically associated with hematological malignancies rather than melanomas. Understanding these distinctions helps in making a more accurate diagnosis and treatment plan.