Case Number : Case 1712 - 20 December - Dr Uma Sundram Posted By: Guest

Dr Uma Sundram has posed you a great little case today.

Cheers, Geoff Cross - DermpathPRO Projects

By low power I was thinking on cellular blue nevus, but the epidermal consumption, thick melanic pigment, nuclear atypia and superficial mitotic figures.... I prefer to call this melanoma.

I don't know if multiple myeloma has been described in the set of Carney syndrome, but my first spot is Pigmented Epithelioid Melanocytoma. 

As my colleague Vincenzo I thought of pigmented epithelioid melanocytoma but overall extreme cellularity, size, clinical setting and clear compromise of adnexae by atypical nesting melanocytes make this case for me a melanoma with epithelioid melanocytoma like morphology

According to Massi and LeBoit’s Histological Diagnosis of Nevi and Melanoma, the adjective benign may be granted to pigmented epithelioid melanocytoma in three circumstances:

• in the setting of Carney complex;
• combined with another type of nevus; or
• with maturation in its deeper reaches into blue nevus, Spitz nevus, or other forms of nevus.

Apart from these three circumstances, the adjective malignant may be placed before pigmented epithelioid melanocytoma due to its potential metastatic involvement of regional lymph nodes, though that do not imply high risk of systemic/visceral metastatic spread which might deserve agressive therapy.

Here there is an additional problem as we are dealing with an incompletely excised specimen. This lesion should be re-excised to ensure clear margins. Maybe sentinel lymph node biopsy will be required because the further examination of the entire lesion is likely to reveal no exclusion criteria for malignancy.

This is a very interesting case. I appreciate Raul's comments. It looks like a malignant lesion, and probably this is the truth. I would call this case melanoma, without knowledge about particular new entries on melanocytic pathological chapter ...and maybe there is a lot of confusion ( mainly in my brain ), so I'm put in mind this is an atypical case (or malignant) case of PEM ( animal type malignant melanoma ). 

Moreover, just joking with morphology, the fig 1,2,5,6 make me think of a pigment laden clear cell sarcoma... ( but not for diagnostic purposes!!! ). What do you Colleagues think about?

As Robledo has said we are dealing with an incompletely excised lesion. I think this is a malignant blue naevus ( or at-least an atypical cellular blue naevus). The distinction is on mitotic cut-offs and presence/absence of necrosis. Definitely needs complete excision and a SLNB.

I considered pigmented epithelioid melanocytoma or Maybe cellular blue nevus.  But some features favor melanoma.  I would do FISH study. Definitely reexcise 

Hi everyone, we had the same differential. Melanoma versus some sort of atypical cellular blue nevus/pigmented epithelioid melanocytoma. The patient is older and the lesion is quite mitotically active, much more than a lesion of low or uncertain malignant potential. We recommended a re excision and a sentinel lymph node biopsy, which he qualified for. The patient did not have Carney complex. Regarding Vincenzo's comment, this is precisely the reason why I put this case out! I thought the morphology was so interesting, with a variety of different entities on the differential, and the case generated a very nice discussion that we could all learn from.

what was the final diagnosis after examining the re-excision specimen/sentinel node status Uma...