Case Number : Case 2642 - 21 August 2020 Posted By: Dr. Richard Carr

Posted for 18 hours, 153 views and no comments! Perhaps everyone has cleared off for the weekend, so I'll have a go.

I see a crateriform, ulcerated tumour with pushing deep borders.  There are areas of haemorrhage which I take to be secondary to tumour necrosis. The cells have a distinctly trichilemmal character to them with pale cytoplasm with mild to moderate nuclear pleomorphism.  There are abundant mitoses, and also Pagetoid spread into the epidermis with some dyskeratotic cells visible.

I favour a trichilemmal carcinoma (follicular SCC).  IH needed to rule out competitors such as clear cell melanoma, sebaceous carcinoma etc.

Trichilemmal carcinoma (fSCC) is my thought too.

Well done for having a go. It's F100 (female 100 years).

Trichilemmal carcinoma my thought too.

Agree with trichilemmal features, but favor a Sebaceous Carcinoma in situ. 

trichelemmal carcinoma

Okay well done Vincenzo. This is sebaceous carcinoma that is in situ for practical purposes (completely circumscript and pushing only borders with no hint of elastic or collagen entrapment (EVG). Please note the amphophilic nature of the cytoplasm, nuclei & nucleoli which are typical for sebaceous tumours. Also the nuclei with squared off edges, due to cytoplasmic vacuoles, is typical as well as the holocrine type pink bubbly secretions. Also typical is the dual positivity for BerEP4 & EMA. What may have passed you by is a "new" aberrant pattern on p16 (E6H4 clone). In inflamed & reactive sun-damaged squamous epithelium and follicles and benign lesions p16 typically shows a nice mosaic / checkerboard staining with nuclear & cytoplasmic. The nuclear positivity, in this reactive / wild type staining, is clearly above the background cytoplasmic staining. In this case we have a wishy washy diffuse, weak to moderate, staining pattern in which nuclei are NOT stained above the background cytoplasmic staining. p53 is also completely null (regarded as indicative of a mutant protein). Note reactive basal cells staining for p53 that is typical of in situ lesions although this may be intermittent. This is another example where EVG staining may be helpful as discussed at length previously.

sir, there is also intra epithelial spread in image 5, that should have given us the clue for sebaceous gland carcinoma

Sir, i was not aware of insitu SGC, how to report it as in situ

Well I'm pretty sure it's under-recognised. See detailed discussion of Case 2622

Thanks a lot sir