PMC6188857_01
Microscopic features of Bednar tumour. (A and B) The tumour is composed of monomorphous spindle shaped cells in a prominent storiform pattern, infiltrating the hypodermal fat in a characteristic "honeycombing" pattern. (C and D) Scattered pigmented dendritic cells are also present. Haematoxylin-eosin stain; original magnification, A, 40x; B and D, 200x; C, 100x.
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Scattered heavily pigmented cells, with round to oval vesicular nuclei and dendritic cytoplasm, were also noted (Figure 1).
Immunohistochemical features of Bednar tumour. (A) Tumour cells are diffusely positive for CD34. Scattered pigmented cells stain positively with Melan-A (B) and S100 (C). Original magnification, A and C, 100x; B, 200x.
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Immunohistochemical investigation of serial sections revealed that spindle cells were positive for vimentin and CD34, but negative for S100, whereas the pigmented dendritic cells resulted positive for S100, but also for Melan-A and HMB-45 (Figure 2).
(A and B) The TC/PET examination shows left axillary lymphoadenopathy, with high 18-fluorodeoxyglucose metabolism. (C and D) Microscopy of the metastasis to satellite lymph node. The epithelioid aspect revealed the origin from the malignant melanoma. The same features were present in the other metastasis to lungs, liver, spleen, and bones (data not shown). Haematoxylin-eosin stain; original magnification, C, 40x; D, 200x.
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fig3
During the 18-month follow-up, the patient developed melanoma satellite skin metastases, multiple colliquative metastatic lymphoadenopathy (Figure 3), metastatic nodules in lungs, liver, spleen and bones, to dorsal vertebrae, with compression of spinal cord at D5 level, and pelvis, microscopically similar to the first metastasis.