Case Number : Case 1458- 26 January Posted By: Guest

An ulcerated cellular tumour composed of rather monomorphic cells with round central nuclei and moderate pale cytoplasm. The cytomorphology makes me think Glomus tumour (?atypical/malignant), although vascular pattern not particularly prominent. Other d/d- myoepithelioma

Will need wide panel of immunos. 

Trichilemmal Carcinoma

Let me to argue better my diagnosis (TC): first i think there is a subtle surface connection of the tumor; then i see a clear appearance of the cells; last, a subtle peripheral palisade. Neck is a typical site for TC.

Ulcerated tumour. Not sure if there is any intact residual epithelium. The first image shows a focus of what looks like tumour necrosis (unless an artefact). The tumour is widely infiltrative, and as Arti has mentioned, has a rather monomorphic appearance. The last image shows some fine granularity and clearing within the cytoplasm of the cells, along with mild and moderate cytonuclear atypia. This tumour needs a wide panel of immunos. Likely to be a primary tumour, epithelial or myoepithelial. Would also rule out a metastasis with IHC.

I also think this is a carcinoma and I liked Vincenzo's suggestion of trichilemmal carcinoma.

I agree that a wide panel of IHQ should be performed but morphology makes me think of clear cell hidradenocarcinoma/ malignant acrospiroma with clear cell change

A bit flumoxed (that means don't know).  Probably an undifferentiated carcinoma, might add some neuroendocrine markers, S100, CD99 (for PNET).

Clear cell hidradenocarcinoma; melanoma markers, synaptophysin, chromogranin and CD99 were all negative.  Cytokeratins positive. Trichilemmal carcinoma would also fit; there were more papillary and cystic areas in other sections which led us to favor clear cell hidradenocarcinoma. A month later the patient had an involved regional lymph node which was diagnosed as malignant based on a cytology/FNA specimen. I was particularly impressed by the relative monotony of the lesional cells, but ulceration and infiltration led us to make the initial diagnosis of malignancy. The initial tumor was also relatively friable and very large, quite worrisome for malignancy clinically.