Richard Carr
@racarr51.bsky.social
Dermatopathologist, Warwick Hospital UK. Interested in all dermatopathology esp. keratocanthoma (KA) & follicular SCC-KA-like. Personal interests: Golf, cider making, dogs - especially fostering guide dogs. Family = No1.
I appreciate there is a single atypical mitotic figure but you should note multinucleation. When a multinucleate cell divides it's mitosis will be atypical. I reported it as a poroma. One more image here (nice coffee-bean).
November 16, 2025 at 6:10 PM
I appreciate there is a single atypical mitotic figure but you should note multinucleation. When a multinucleate cell divides it's mitosis will be atypical. I reported it as a poroma. One more image here (nice coffee-bean).
RAC3910: x4 more images at request of @rishiagrawal.bsky.social
November 16, 2025 at 5:23 PM
RAC3910: x4 more images at request of @rishiagrawal.bsky.social
Sensible. I'll "attach" them to the main post!
November 16, 2025 at 5:21 PM
Sensible. I'll "attach" them to the main post!
RAC9309 My Dx: Poroma with folliculo-sebaceous differentiation, probably PAK2 fusion. pubmed.ncbi.nlm.nih.gov/37199682/
Recurrent PAK2 rearrangements in poroma with folliculo-sebaceous differentiation - PubMed
Recurrent fusions involving the PAK2 gene in all analysed poroma with folliculo-sebaceous differentiation in this study confirms that this neoplasm represents a separate tumour entity distinct from YAP1::MAML2 or YAP1::NUTM1 rearranged poromas.
pubmed.ncbi.nlm.nih.gov
November 16, 2025 at 11:42 AM
RAC9309 My Dx: Poroma with folliculo-sebaceous differentiation, probably PAK2 fusion. pubmed.ncbi.nlm.nih.gov/37199682/
RAC9306: EVG & Commentry. Then MSH6 (loss) & PMS2. Advised referral to medical genetics to rule out Muir Torre Syndrome (familial cancer associated syndrome).
November 4, 2025 at 7:05 AM
RAC9306: EVG & Commentry. Then MSH6 (loss) & PMS2. Advised referral to medical genetics to rule out Muir Torre Syndrome (familial cancer associated syndrome).
RAC9300: IHC as requested @rishiagrawal.bsky.social
October 30, 2025 at 8:34 AM
RAC9300: IHC as requested @rishiagrawal.bsky.social
Yes reactive (mosaic for p16, peripheral graded or wild type matching Ki67 distribution in lesions were basal / germinative cells a dominant). Some benign lesions have >proliferation c/w p53 expression. I believe this is a case in point.
October 27, 2025 at 9:38 PM
Yes reactive (mosaic for p16, peripheral graded or wild type matching Ki67 distribution in lesions were basal / germinative cells a dominant). Some benign lesions have >proliferation c/w p53 expression. I believe this is a case in point.
RAC9306. EVG & Discussion. I thought this was a mitotic sebaceoma / sebaceous adenoma. MSH6 & PMS2 requested. So far been sceptical about clear-cut Seb Ca & MTS. See a lot mitotically active lesions erroneously called carcinoma.
October 27, 2025 at 3:58 PM
RAC9306. EVG & Discussion. I thought this was a mitotic sebaceoma / sebaceous adenoma. MSH6 & PMS2 requested. So far been sceptical about clear-cut Seb Ca & MTS. See a lot mitotically active lesions erroneously called carcinoma.
RAC9306: IHC Montages, EVG & Comment Summary to follow
October 27, 2025 at 3:56 PM
RAC9306: IHC Montages, EVG & Comment Summary to follow
4me no overtly worrying features for malignancy. Yes no applique. Sebceomas can by highly mitotic (like pilomatrixoma). Benign adnexal lesions are often patchy weak mosaic (in my studies p16 tends to be much higher in Seb Ca). Additional IHC/EVG/BerEP4/EMA & comments posted.
October 27, 2025 at 3:55 PM
4me no overtly worrying features for malignancy. Yes no applique. Sebceomas can by highly mitotic (like pilomatrixoma). Benign adnexal lesions are often patchy weak mosaic (in my studies p16 tends to be much higher in Seb Ca). Additional IHC/EVG/BerEP4/EMA & comments posted.
RAC9300. Lower powers. @rishiagrawal.bsky.social #dermpath
October 27, 2025 at 3:41 PM
RAC9300. Lower powers. @rishiagrawal.bsky.social #dermpath
RAC9306: IHC here p16, p53, Ki67 @rishiagrawal.bsky.social These are representative.
October 27, 2025 at 3:38 PM
RAC9306: IHC here p16, p53, Ki67 @rishiagrawal.bsky.social These are representative.
👍 Broekaert...Kazakov. Squared-Off Nuclei and "Appliqué" Pattern as a Histopathological Clue to Periocular Sebaceous Carcinoma: A Clinicopathological Study of 50 Neoplasms From 46 Patients. Am J Dermatopathol. 2017 Apr;39(4):275-278. PMID: 28323778.
Applique is characteristic but not specific IMO.
Applique is characteristic but not specific IMO.
October 17, 2025 at 7:36 AM
👍 Broekaert...Kazakov. Squared-Off Nuclei and "Appliqué" Pattern as a Histopathological Clue to Periocular Sebaceous Carcinoma: A Clinicopathological Study of 50 Neoplasms From 46 Patients. Am J Dermatopathol. 2017 Apr;39(4):275-278. PMID: 28323778.
Applique is characteristic but not specific IMO.
Applique is characteristic but not specific IMO.
Yes. Read discussions with @rishiagrawal.bsky.social For me a reactive PATTERN rather than a single entity and not a neoplasm. Relatively common and usually overlying bony prominences. I report at least one or two a year.
October 17, 2025 at 7:28 AM
Yes. Read discussions with @rishiagrawal.bsky.social For me a reactive PATTERN rather than a single entity and not a neoplasm. Relatively common and usually overlying bony prominences. I report at least one or two a year.
I often do EVG in such cases if I think it will affect management. Completely circumscript borders with no entrapment we regard as supporting in situ and more likely to consider "watchful waiting".
October 17, 2025 at 7:23 AM
I often do EVG in such cases if I think it will affect management. Completely circumscript borders with no entrapment we regard as supporting in situ and more likely to consider "watchful waiting".
Yes FSCC. mainly in situ. In UK pT1 low risk are not followed up unless margins are close. I think I also favoured focal invasion. Margin was positive but I may have said "watchfull waiting may suffice". I'll check on that.
October 17, 2025 at 7:20 AM
Yes FSCC. mainly in situ. In UK pT1 low risk are not followed up unless margins are close. I think I also favoured focal invasion. Margin was positive but I may have said "watchfull waiting may suffice". I'll check on that.
This lesion lacks neutrophil microabscesses and more importantly no signs of regression. With IHC highly aberrant null/weak only p53 FSCC-KA-LIKE is favoured.
October 9, 2025 at 6:23 PM
This lesion lacks neutrophil microabscesses and more importantly no signs of regression. With IHC highly aberrant null/weak only p53 FSCC-KA-LIKE is favoured.
Agreed. Mosaic p16 but highly aberrant null +/- weak only p53. Favours FSCC-KA-like.
October 9, 2025 at 6:20 PM
Agreed. Mosaic p16 but highly aberrant null +/- weak only p53. Favours FSCC-KA-like.