Case Number : Case 1501- 25 March Posted By: Guest

Agree with Mona sebaceous carcinoma with squamous metaplasia. A differential could be a collision tumor but the áreas of squamous differentiation dont seem atypical in this case

I am also thinking of the possibility suggested by Raul: a collision tumor, sebaceous and squamous cell carcinoma.

Agree, Sebaceous Carcinoma (infiltrative focally) with squamous differentiation. Maybe a bit too old but consider Muir Torre Syndrome? Have seen it in rare cases, present very late

Agree with sebaceous carcinoma.

Thanks for all the excellent responses.  I am on a little holiday hence delay in my post.  I called this sebaceous carcinoma with tricholemmal (follicular) carcinoma-like areas.  The lobulated, folliculocentric pattern is seen in the low powers and I suspect the lesion is overwhelmingly in situ so should have a very good prognosis.  I guess this is another example of a hybrid sebaceous-follicular-apocrine duct unit neoplasm. Of course the sebaceous duct drains in to the hair follicle so this combination is not entirely surprising or perhaps it is to be expected.  I don't recall having seen a case like this previously where the two differentiations were so well formed but also intermixed. It is funny when we see a tumour with squamous differentiation and another differentiation e.g. sebaceous or glandular the latter defines the classification.  Perhaps it is more precise to acknowledge the hybrids e.g. Carcinoma with sebaceous and follicular tricholemmal differentiation. The age and site would be most unusual for Muir Torre but no harm in mentioning that it is unlikely to be associated with Muir Torre in the report to remind the clinical colleague to think of the possibility.