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Richard Carr

@racarr51.bsky.social
157 followers 54 following 265 posts

Dermatopathologist, Warwick Hospital UK. Interested in all dermatopathology esp. keratoacanthoma (KA) & follicular SCC-KA-like. Personal interests: Golf, cider making, dogs - especially fostering guide dogs. Family = No1.

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Richard Carr @racarr51.bsky.social · 23/06/2026
thx for replying. Seems Bluesky is lacking much interactive activity in Dermpath.
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Richard Carr @racarr51.bsky.social · 21/06/2026
RAC9375. F70s. Nasal alar. ?KA ?SCC, additional pathology. What is this rare combo of p16 & p53?
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Richard Carr @racarr51.bsky.social · 21/06/2026
RAC9375. F70s. Nasal alar. 9 weeks ?KA ?SCC
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Richard Carr @racarr51.bsky.social · 15/04/2026
Yes, Spitz / Reed n. Has rather large Kamino bodies (paler pink, ltd to DEJ, usually scalloped, will b collagen type IV+). Larger more irregular aggregates are probably clustered colloid bodies (necrotic keratinocytes dropped into papillary dermis) HMW CK would confirm.
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Richard Carr @racarr51.bsky.social · 15/04/2026
I thought interstitial palisading granulomatous pattern & collagen necrobiosis = GA. Unusual 2C well-formed granulomas and Langhan-type giant cells!! Suspect nerve, lacks intra-neural inflammatory cells, incidental. pubmed.ncbi.nlm.nih.gov/25140662/
pubmed.ncbi.nlm.nih.gov
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Richard Carr @racarr51.bsky.social · 15/04/2026
Looks like but was NOT a KA, see discussion thread and IHC stains: SPLUMP KA-like or FSCC Fav'd. Clue on H&E beware a lesion w actively proliferating but pushing rounded borders & no regression - more likely 2B FSCC. Proliferative KA r highly infiltrative (rounded bowl shape only in LP profile).
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Richard Carr @racarr51.bsky.social · 15/04/2026
Well there is a nerve surrounded by tumour. I normally only report PNI when it is extending around a nerve beyond the main outlines of the tumour borders. In this case it does appear to be following a neurovascular bundle though.
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Richard Carr @racarr51.bsky.social · 28/03/2026
I don't really have a good name. Agree benign basaloid proliferation in a naevus. Not in the textbook 😇
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Richard Carr @racarr51.bsky.social · 28/03/2026
In my experience AFX-type cutaneous sarcoma / PDS are usually either highly aberrant null or cytoplasmic only for p16. This is an uncommon exception which is mosaic. I interpreted p53 as null. Ki67 was low in keeping with an indolent variant. Never seen a case metastasise personally.
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Richard Carr @racarr51.bsky.social · 17/03/2026
Good thoughts: Here CK20, CD10, BerEP4, MelanA
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Richard Carr @racarr51.bsky.social · 17/03/2026
RAC9366: IHC for "malignant spindle tumour on H-CSD skin: CD10 = 60%, S100-, a pan-keratin- & p63- not shown. I don't do other markers unless clues. Do p16, p53 & Ki67 as here when lesions are indolent as in this case. Thoughts? #Dermpath @rishiagrawal.bsky.social
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Richard Carr @racarr51.bsky.social · 14/03/2026
RAC9366 M70s. Scalp Vertex. ?SCC #dermpath @rishiagrawal.bsky.social
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Richard Carr @racarr51.bsky.social · 11/03/2026
RAC9365. F80ish. Pre-auricular ?BCC. #Dermpath @rishiagrawal.bsky.social
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Richard Carr @racarr51.bsky.social · 11/03/2026
Yes SPLUMP KA-like or FSCC Fav'd. KAscore (or maybe "CarrKAscore" = "uncertain" ~19% (100*6/32). Clue on H&E beware a lesion w actively proliferating but pushing rounded borders & no regression - more likely 2B FSCC. Proliferative KA r highly infiltrative (rounded bowl shape only in LP profile).
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Richard Carr @racarr51.bsky.social · 11/03/2026
Agree but nevertheless I thought this might be a Becker given the clinical suggestions. There are rare reports of large bilateral lesions.
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Richard Carr @racarr51.bsky.social · 11/03/2026
Interesting. Confess I was not aware of role of SLNBx in this setting. Is there not a move to treat the LN basin with DXT in any case? & Victor mentioned good responses to immune modulators so would it not make more logical sense to give neoadjuvant prophylactically - maybe the risk profile?
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Richard Carr @racarr51.bsky.social · 08/03/2026
RAC9364: Great observations. Here is the IHC: x3 for p16 and x1 for p53.
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Richard Carr @racarr51.bsky.social · 08/03/2026
Good thought. Clinical was ?giant congenital naevus ?Becker's naevus.
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Richard Carr @racarr51.bsky.social · 08/03/2026
RAC9364 M70 ish. Upper chest. 30 x 20mm keratotic nodule ?SCC. #Dermpath @rishiagrawal.bsky.social
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Richard Carr @racarr51.bsky.social · 26/02/2026
RAC9358. M40s Bilateral giant pigmented lesion. Biopsy from chest. #Dermpath @rishiagrawal.bsky.social
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Richard Carr @racarr51.bsky.social · 21/02/2026
I thought interstitial palisading granulomatous pattern & collagen necrobiosis = GA. Unusual 2C well-formed granulomas and Langhan-type giant cells!! Suspect nerve, lacks intra-neural inflammatory cells, incidental. pubmed.ncbi.nlm.nih.gov/25140662/
pubmed.ncbi.nlm.nih.gov
Granuloma Annulare Mimicking Sarcoidosis: Report of Patient With Localized Granuloma Annulare Whose Skin Lesions Show 3 Clinical Morphologies and 2 Histology Patterns - PubMed
Granuloma annulare, a benign dermatosis of undetermined etiology, typically presents in a localized or generalized form. It has 3 distinctive histologic patterns: an infiltrative (interstitial) pattern, a palisading granuloma pattern, and an epithelioid nodule (sarcoidal granuloma) pattern. A man wh …
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Richard Carr @racarr51.bsky.social · 21/02/2026
I asked for follow-up. Incidentally there is a small nerve closely associated. You can see a neuritis in morphoea (that is not due to leprosy - Eduardo Calonje showed a lovely case at an Anglo-Belgium-French meeting a few years ago.
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Richard Carr @racarr51.bsky.social · 21/02/2026
I think I might have requested alcian blue. No bug stains. History was what I had.
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Richard Carr @racarr51.bsky.social · 21/02/2026
Positive - it's very good at staining the inner aspect of ORS at all levels up to isthmus and sebaceous duct linings.
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Richard Carr @racarr51.bsky.social · 21/02/2026
I thought this was typical for morphoea. I've asked for follow-up. Not much literature but looks like patients with morphoea can get lesions incited by trauma or friction. PMID: 24880663. pubmed.ncbi.nlm.nih.gov/24880663/
pubmed.ncbi.nlm.nih.gov
The role of skin trauma in the distribution of morphea lesions: a cross-sectional survey of the Morphea in Adults and Children cohort IV - PubMed
Of patients in the MAC cohort, 16% developed initial morphea lesions at sites of skin trauma. If these findings can be confirmed in additional series, they suggest that elective procedures and excessive skin trauma or friction might be avoided in these patients.
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Richard Carr @racarr51.bsky.social · 21/02/2026
Checked database only ~5 cases only. None wiht IHC. Expect CD34 negative usually a feature of mid-stem/lower outer ORS as in tricholemmoma although does stains about 50% of proliferating pilar tumours. Calretinin definitely. But it would be academic.
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Richard Carr @racarr51.bsky.social · 21/02/2026
Yes well done. Not common. Usually cells pinker (isthmic). Ackerman made points - better classified as tumour of follicular isthmus part of upper ORS. Usually incidental.
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Richard Carr @racarr51.bsky.social · 21/02/2026
RAC9356: Not my diagnosis. A few more images.
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Richard Carr @racarr51.bsky.social · 20/02/2026
RAC9356. M60s. Re-excision of thin melanoma (7 weeks from prior excision). What's going on? @rishiagrawal.bsky.social #dermpath
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Richard Carr @racarr51.bsky.social · 20/02/2026
Nice one Charles. I would have accepted your case as myrmecia (can you take another look - seems to have pretty substantial inclusions to me).
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Richard Carr @racarr51.bsky.social · 20/02/2026
RAC9355 F60s. Lower back. ?BCC for opinions please. Also what type of giant cell? @rishiagrawal.bsky.social #Dermpath
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Richard Carr @racarr51.bsky.social · 20/02/2026
Sorry for @rishiagrawal.bsky.social
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Richard Carr @racarr51.bsky.social · 16/02/2026
RAC9352. M70s. Cheek. BCC excised. Adjacent lesion. #dermpath @iyengarish.bsky.social
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Richard Carr @racarr51.bsky.social · 07/02/2026
Agree. This case has a lot of mosaic p16 in the reactive follicular hyperplasia. Cases like this are why KA and FSCC-KAL can't be reliably distinguished on H&E. IHC is a game changer.
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Richard Carr @racarr51.bsky.social · 04/02/2026
RAC9342: This was outsource case with no other clinical information. Top 2 are p16 bottom 2 are p53.
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Richard Carr @racarr51.bsky.social · 27/01/2026
RAC9342: M70s Base of thumb. SCC excision. @rishiagrawal.bsky.social #dermpath
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Richard Carr @racarr51.bsky.social · 27/01/2026
RAC9339: How about these two stains: MSH6 & PMS2?
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Richard Carr @racarr51.bsky.social · 27/01/2026
Agree. Anything else to consider regarding the patient?
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Richard Carr @racarr51.bsky.social · 26/01/2026
Sorry RAC9339
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Richard Carr @racarr51.bsky.social · 26/01/2026
RAC9340 Excellent: It was ~7mm in clinic at 7 weeks increased to 11mm at 13 wks when shaved. Clinically ?KA ?SCC. Here p16 & p53 x2 each.
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Richard Carr @racarr51.bsky.social · 26/01/2026
RAC9339. M50 ish. Nasal bride. Started as a spot. Grew to nodule centrally keratotic, shaved at 13 weeks. Clin photo at 7wks. @rishiagrawal.bsky.social #Dermpath
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Richard Carr @racarr51.bsky.social · 26/01/2026
Good, she had best paper on cerebral malaria BTW! You might have got Maria Magdalena Dąbska. I missed Georgina Hogg a pathologist (of Birt-Hogg-Dube). Others either Clinicians e.g. Liliane Schnitzler - derm, Katherine Krom Merritt - paed (Kasaback-Merritt); Sister Mary Joseph (Nodule)
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Richard Carr @racarr51.bsky.social · 25/01/2026
Correct. Can be confused with colloid bodies (necrotic keratinocytes). Kamino tend to be pale pink and scalloped & ltd to DEJ. Colloid bodies stronger stained, rounded & drop below DEJ - keratin +ve. Latter are common in bulky & atypical Spitz. Any other female eponyms in Dermpath?
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Richard Carr @racarr51.bsky.social · 23/01/2026
Any info on RB1 loss?
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Richard Carr @racarr51.bsky.social · 23/01/2026
Agree. Follow-up. No AI/Google. Who was Kamino? What are Kamino bodies?
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Richard Carr @racarr51.bsky.social · 21/01/2026
RAC9338: Spot Diagnosis @rishiagrawal.bsky.social #Dermpath PLEASE DISCUSS
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Reposted by Richard Carr
I Quit Smoking 🚭 📚 🐕 @iquitcigs.bsky.social · 15/01/2026
My Copy I have given away at least 20 of these to smokers or their spouse. Best Book ever on Quitting Here is his son @racarr51.bsky.social...
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Reposted by Richard Carr
Richard Carr @racarr51.bsky.social · 14/01/2026
I mentioned your hilarious post to Robin (CEO, Easyway) & perhaps you read the apparently hilarious self-help spoof book he knew about:
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Richard Carr @racarr51.bsky.social · 14/01/2026
I mentioned your hilarious post to Robin (CEO, Easyway) & perhaps you read the apparently hilarious self-help spoof book he knew about:
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Reposted by Richard Carr
Richard Carr @racarr51.bsky.social · 31/12/2025
Brilliant & well done. Funny thing though it really is EASY to stop if you know psychological aspect. Physical addiction is minimal (no cold turkey). Cunning trick : smokers believe +/- they enjoy & / or r hopelessly addicted. My dad's book explains all (I'm a doctor BTW - don't get royalties😇).
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