Desmoplastic melanoma commonly occurs on the head and neck in a pure form, but occasionally, it occurs in a mixed tumor with another type, usually superficial spreading melanoma (SSM), and rarely as a metastasis from a primary SSM. We report here a primary SSM on the leg of a 32-year-old male which metastasised to lymph nodes, and 10 years later recurred at the primary site initially with mixed features but evolving to resemble a uniformly desmoplastic, deeply invasive melanoma. This unusual case has implications for clinical management and is additionally notable for its reversal in behavior, from metastatic to local infiltrative type, correlating with the change in morphology.

促纤维增生性黑色素瘤通常以纯粹形式发生在头部和颈部，但偶尔也发生在与另一种类型的混合肿瘤中，通常是浅表扩散性黑色素瘤（SSM），很少是原发性 SSM 的转移。我们在这里报道了一名 32 岁男性腿部的原发性 SSM，该病已转移至淋巴结，10 年后在原发部位复发，最初具有混合特征，但逐渐演变成类似于均匀促纤维增生、深度侵袭性黑色素瘤。这种不寻常的病例对临床治疗具有重要意义，而且值得注意的是它的行为逆转，从转移型到局部浸润型，与形态学的变化相关。