Patient with history of myelomonocytic leukemia post treatment, below is a follow up flow cytometry analysis of his peripheral blood months later, showing an expanded population in the CD45-dim gate (aka "blast-gate") #hemepath #PathTwitter #leusm #MedEd #MedTwitter #MedX @saada_vsaada This population is negative for CD14, CD33, CD34, C64, CD117, CD123 & HLA-DR expression; However, it shows subset CD13 expression #hemepath #PathTwitter #leusm #MedEd #MedTwitter #MedX

Viral infections may show striking T-cell atypia; which in the absence of adequate clinical history, may be worked-up for T-cell lymphoma

Below are pictures from a peripheral blood smear of a patient with an acute viral illness & remarkable lymphocytic atypia #hemepath #lymsm Flow cytometry analysis confirms the nature of these numerous atypical cells by morphology as lymphocytes, with a predominant CD3-positive T-cell population #hemepath #lymsm #PathTwitter #PathX #SoMe #MedTwitter

Tricky case of Cyclin-D1-positive neoplasm➡️

Patient presented with "pancytopenia, rule out MDS"

Flow cytometry of a limited marrow aspirate revealed a CD20-positive Kappa restricted population that appeared to be negative for CD19 expression #hemepath #lymsm #mmsm #MedTwitter

Morphologic examination showed a hypercellular marrow almost completely involved by a "lymphoid" infiltrate with a low grade morphology

An incredibly challenging case of ALK-rearranged poorly differentiated lung adenocarcinoma with diffuse CD30 positivity, mimicking ALK-rearranged Anaplastic Large Cell Lymphoma, first authored by future #hemepath🌟@gibyvgeorge ➡️ #lymsm @Histo_Journalonlinelibrary.wiley.com/doi/10.1111/hi… Patient presented with a mediastinal mass, composed of sheets of anaplastic cells. Cytokeratin stains along with CD45 & all B-cell & T-cell markers were negative
#hemepath #lymsm #pathtwitter #pathX #molpath #medtwitter #surpath #cytopath #thoracicpath

Patient with history of CLL/SLL clinically progressing; Below bone marrow biopsy shows complete involvement by lymphoma

#lymsm #hemepath #PathTwitter #pathx #surgpath #MedTwitter #bmtsm High power evaluation: 2 components detetcted, the yellow circle is the CLL/SLL component, and the yellow arrows point at larger pleomorphic cells #lymsm #hemepath #PathTwitter #pathx #surgpath #MedTwitter #bmtsm

CLL/SLL with an inter & peri-follicular architecture ⬇️⬇️

#hemepath #PathTwitter #lymsm #pathX #surgpath The neoplastic lymphocytes surround germinal centers; If the neoplastic cells had more of a "monocytoid" look, with this perifollicular architecture, this lymphoma could be easily misinterpreted as nodal marginal zone lymphoma, particularly in limited core-nedle biopsy

#hemepath

Stage III Hematogones can express CD5, and this may cause overinterpretation as residual CD5+ B-cell lymphoma. Let's go through 2 examples below that nicely illustrate this⬇️

@ICCS_Education @saada_vsaada #hemepath #Xpath #PathTwitter #MedTwitter #surgpath #lymsm In the example below of a bone marrow flow cytometry analysis, SCC against CD45 plot, you can nicely see the 3 stages of Hematogones, with stage 3 blending in with mature B-lymphocytes #hemepath #Xpath #PathTwitter #MedTwitter #surgpath #lymsm #leusm

CLL/SLL initially presenting as skin lesions, with plasmacytic differentiation, real entity or myth?

🩸Below is an illustration of low grade B-cell lymphoma with a CLL phenotype & monotypic plasma cells

#hemepath #PathTwitter #lymsm #MedTwitter #dermpath #surgpath





🩸CD5+ LPL is on top of the differential & must be ruled out, as do as low grade B-cell lymphomas that can show common features with CLL phenotype
🩸Mantle cell lymphoma & follicular lymphoma can also demonstrate plasmacytic differentiation

#hemepath #PathTwitter #lymsm

Have you had a pediatric B-ALL with very mature features previously, that made you question whether you are dealing with a B-cell lymphoma instead? Below is a similar case:

Starting with CD38 expression: It is not as "dim" as you would expect it to be in B-ALL

#Hemepath #Leusm Moving to CD10, which is considered a marker of immaturity, it is absent below

#Hemepath #Leusm #MedTwitter #bmtsm #pathtwitter #molpath @ICCS_Education @saada_vsaada

It is known that B-ALL with KMT2A rearrangement may undergo lineage switch after therapy. See below a KMT2A-R B-ALL case switching to an AML (CD34+ HLA-DR+) after treatment, then switching to a monocytic leukemia (CD14+ CD64+/CD34- HLA-DR-) 2 years later
#hemepath @ICCS_Education Starting with the B-ALL at presentation, positive for CD19, CD22 & CD79a

#hemepath #PathTwitter #leusm #lymsm #BALL #BMTSM #MedTwitter #molpath

The many faces of plasma cell neoplasm, diagnostic challenges of the great imitator in #hemepath ➡️bit.ly/3B3jMC1 with @ljmedeirosMD & @ShiminHuMDPhD #mmsm #lymsm #pathtwitter #leusm 1) The small cell variant (mimicking B-cell lymphoma, particularly mantle cell lymphoma➡️CyclinD1 positive) #hemepath #pathtwitter

(1/6) Future #dermpath star, @DermpatGal, & I have put together an illustration of hematologic findings in "Drug Reaction with Eosinophilia & Systemic Symptoms" (DRESS) @AjHematology ➡️ bit.ly/3u9WvLa

#hemepath #pathtwitter @Pathology_URMC 🔬

#Tweetorial ⬇️ (2/6) Drug metabolites (commonly of anti-anticonvulsant medication) are thought to stimulate T-cells leading to a florid immune response/ or cause viral activation (HHV6) leading to downstream immune activation

(Pathogenesis of DRESS➡️bit.ly/3F3uKJp @MDPIOpenAccess )

(1/5) AML with NPM1 mutation ⬇️

Characteristically prominent nuclear invaginations imparting a “cup-like” or “fish-mouth” morphology, with very strong MPO positivity 🔬

@KirillLyapichev @sanamloghavi

#hemepath #hemepathMDA #PathTwitter (2/5) Cytoplasmic staining of NPM1 protein by IHC is predic­tive of NPM1 mutations

#hemepath #hemepathMDA #PathTwitter

One of the many pearls that I learned from @ljmedeirosMD is:"The best time to learn, is after you know the diagnosis of a case, by going back to the slides and reading more about it".In this spirit, below are the answers of today's cases, with pictures #hemepath @KirillLyapichev

https://twitter.com/SibaElHussein/status/1268642793406242817

Case 1 : Marginal zone lymphoma

#hemepath #hemepathMDA #virtualhemepathMDA #virtualhemepath #virtualpath