Angiotropism is an independent predictor of microscopic satellites in primary cutaneous melanoma

To establish whether microscopic angiotropism of melanoma cells correlates with microscopic satellite (MS) formation in cutaneous melanomas and thus is likely to explain the development of MS.

Patients with MS and controls without MS from 1996 to 2009 were evaluated for the presence or absence of angiotropism. MS was defined as a dermal/subcutaneous tumour nodule >0.05 mm, separated from the primary tumour by at least 0.3 mm. Forty four cases and controls were matched for tumour thickness, mitotic rate, ulceration, age, gender and primary site. Angiotropism (23 of 44, 52%) and absent regression (19 of 44, 43%) were significantly more frequent in melanomas with MS than in those without MS (controls) (12 of 44, 27%) (P = 0.017) and (32 of 44, 73%) (P = 0.005), respectively. Factors correlating with angiotropism included increased Clark level (P = 0.046), regression absence (P = 0.02) and MS (P = 0.017). On multivariable analysis, MS formation was predicted by angiotropism (P = 0.026), Clark level V (P = 0.01), absent regression (P = 0.009) and acral site (P = 0.02).

Angiotropism predicts MS development. These data provide additional evidence for the importance of angiotropism as a means of melanoma metastasis.