Case Number : Case 1777 - 21 March - Dr Uma Sundram Posted By: Guest

Tuesday wouldn't be Tuesday without Dr Uma Sundram's Spot Diagnosis Case, enjoy.

Geoff Cros - DermpathPRO Projects

Would perform a nuclear marker like sox-10 or MITF to better see the presence of a dermal component. However this does not change the fact that there is quite some confluence, disorganization, irregular pigmentation and detachment of cells as wells as prominent lymphocytic infiltrate (Sutton's nevus-like). For me this is melanoma to determine if in-situ or not by IHC (I favor in situ based on the images). I am not sure if there is also a junctional nevus component (pic2).

Melanoma 

Agree- looks like a melanoma. Suspicious of invasion

Agree with Mona, Raul and Sasi

Right half shows more worrisome lentiginous and confluent wrecking of basal epidermis than left one ( asymmetry ) leading towards melanoma.

The low-power silhouette shows an asymmetric melanocytic proliferation, and the high-power view captured on the last image reveals nests apparently located in the papillary dermis. Those nests are composed by melanocytes with nuclei that are hyperchromatic and pleomorphic. Some melanocytes appear as multinucleated giant cells. Brisk mitotic activity can be found. All those microscopic findings, taken together to the clinical history of a suspicious (if it were not suspicious, it would not be excised) pigmented lesion on the lower limb of a middle-aged to elderly women, make me favor melanoma in vertical growth phase.

I agree to melanoma

Agree, melanoma. A rather untidy junctional component, inflammatory response. Would do a Melan-A to delineate the dermal component better.

Agree...favour in situ melanoma, not convinced there is a dermal component, but would do a melan A.

Melanoma. I cant distinguish an invasive component from these images. 

Melanoma in situ. We did an MITF and there was no dermal component. I would add a caveat about Melan A staining on its own, as this stain tends to highlight degenerating keratinocytes too, especially in lichenoid lesions like this one. I included this case as lichenoid MMIS is not well reported in the literature (please see below).

Lichenoid tissue reaction in malignant melanoma: a potential diagnostic pitfall.