PMC10162761_01
Squamomelanocytic tumour. (a) Clinical image of a black ulcerated tumour in the mandibular angle. (b) Low-power magnification showing nests of atypical melanocytes with admixed squamous cell carcinoma (x4.6). (c) High-power magnification depicting the intermingling of pleomorphic keratinocytes and atypical melanocytes (x10.2). (d) Immunohistochemical staining with MELAN-A showing melanocytic component (x9.6). (e) Immunohistochemical staining with cytokeratin AE1/AE3 showing squamous component (x7.9)
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F1
On physical examination, he presented a one-centimetre black ulcerated tumour [Figure 1a]. AE1/AE3, cytokeratin 5/6 and epithelial membrane antigen [Figure 1b-e]. A diagnosis of SMT was rendered.
Collision of melanoma in-situ with seborrheic keratosis. (a) Clinical image of an asymmetric macule with irregular, poorly defined borders and heterochrome pigmentation in the forehead. (b) Low-power magnification showing a collision of a melanoma in-situ, lentigo maligna type, with a seborrheic keratosis (black arrows) (x 7.7). (c) High magnification of melanoma in-situ component, with nests of atypical melanocytes along dermal-epidermal junction (x33.4). (d) Immunohistochemical staining with MELAN-A showing melanocytic component (x15.8)
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F2
At the same time, a two-centimetre asymmetric macule with poorly defined borders and heterochrome pigmentation in the forehead was found [Figure 2a].