Thread by @DrStevenTChen

Hello new followers!👋 In honor of your joining me on Twitter, I thought I'd put together a new #dermatology #tweetorial/#medthread. This time, on a topic near and dear to my own clinical practice:

MYCOSIS FUNGOIDES!

#MedEd #FOAMEd #Dermtwitter #Medtwitter pc: @dermnetnz
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Let's start w/ caveats:
1-#MycosisFungoides (MF) isn't the same as Cutaneous T-cell Lymphoma. MF is a subtype of #CTCL; there are many other types of CTCL that aren't MF.
2-I co-direct the Skin Lymphoma Program @MGHCancerCenter, so some of this is institutional preference.
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There are roughly 80,000 new cases of #lymphoma a year in the US, and only 3% are primary cutaneous. Within that ~2500 cases, MF makes up almost half (~44%)! The overall classification schema for these diseases was recently updated by the WHO:
bloodjournal.org/content/133/16…
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Let's focus on MF. Early stage (pic1) classically is described as atrophic pink plaques with fine scale. The atrophy sometimes looks like "cigarette paper" and a bathing suit distribution is typical. Later stages can have tumors (pic2), or even erythroderma on exam (pic3).
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While any of these findings on exam might raise your suspicion of MF, a biopsy is usually necessary for diagnosis. Findings include "tagging" of atypical lymphocytes as the dermo-epidermal jx, epidermotropism (lymphs going into epi), and loss of certain markers (eg: CDs 2&5).
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Exception to the bx making the dx is in the case of Sezary Syndrome (SS). SS is the "leukemic variant" of MF (but we now know it doesn't have to "arise" from MF). If the patient meets criteria based on blood for SS, that's enough for dx (despite neg path, which is common!).
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Let's say you now have a bx and clinical exam c/w MF. You know that there's no lymphadenopathy and there's no evidence of blood involvement. The exam is described as patch plaque involvement covering ~20% of the BSA. What stage MF does the patient have?
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In our patient, this would be stage 1B disease. See below for the staging, but notice how it's heavily reliant on the clinical exam. The amount of work up is variable by physician, but I don't do routine CT scans with early stage disease, and CBC/d, LDH +/-flow may be it!
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Staging simplified:
Stage 1A - <10% patch/plaque (p/p)
Stage 1B - >10% p/p
Stage 2A - palpable lymph nodes
Stage 2B - Tumors
Stage 3 - erythroderma
Stage 4A1 - SS
Stage 4A2 - LN path w/ MF
Stage 4B - visceral path w/ MF

This matters! Look at the K-M curve based on stage:
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A few tricks/tips I also tell my residents:
- If a patient has palpable LN, has it bx'ed, and read as dermatopathic (aka reactive), they are stage 2A, not 4A2!
- Always send a CBC/d with your flow to calculate absolute numbers.
- CBC/d w/ lymphocytosis -> c/f SS! Send flow!
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So, how do we treat? Early stage MF (meaning 1a-2a) usually is treated with skin directed therapy. This means usually steroids, topical nitrogen mustard, or phototherapy. I also throw methotrexate and bexarotene in there. #dermatologists can totally handle these.
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Later stage MF requires collaboration with an #oncologist. Txs can include things like brentuximab, HDAC-inhibitors, mogamulizumab, ECP, pralatrexate, etc. The only curative therapy is bone marrow transplant, which we usually try to avoid unless absolutely necessary.
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Bottom line, pts with early stage disease usually do well because it's such an indolent process. Those with advanced disease should consider care at a multidisciplinary center for discussion of appropriate therapies! Patients can find centers at: clfoundation.org
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To RECAP:
1-MF is rare, but one of the more commonly seen primary cutaneous lymphomas.
2-Staging is critical for prognostication
3-Early stage disease is indolent and a #dermatologist can direct care.
4-Later stage disease may require multi-D care.
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A final tweet to say thanks to my colleagues @MassGeneralNews, where I get to care for these patients every week w/ #oncology, #radiationoncology, & #dermpath. It's an unbelievably rewarding field, & a great example of when collaboration makes a huge difference for our pts!
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