Basics of Reading Slides for Leukemias in Hematopathology 🧵 🔬 A guide with mnemonics, and practical tips for diagnosing leukemias on slides. Whether you’re reviewing bone marrow biopsies or peripheral smears, here’s what to look for: 1️⃣ Start with the Big Picture (Low Power) 🔍 •Use 10x magnification to assess: •Cellularity: Hypercellularity suggests leukemia 📈. •Look for abnormal clusters or infiltrates 🧱. •Identify necrosis or fibrosis if present. 📝 Mnemonic: “Locate the Leukemia!” 💡 Tip: Compare the sample with normal marrow to catch subtle abnormalities. 2️⃣ Go Higher Power (40x/100x) 👀 •Examine morphology: •Blasts: Large size, high N:C ratio, fine chromatin, nucleoli. •Auer rods: Pathognomonic for AML, especially APL 🚨. •Granules: Common in myeloid blasts. •Cytoplasmic vacuoles: Seen in ALL or Burkitt lymphoma. 📝 Mnemonic: “Big Blasts Have Auer Rods.” 💡 Tip: Document cell sizes, inclusions, and other features systematically. 3️⃣ Identify Key Features by Leukemia Type 🩸 •Acute Myeloid Leukemia (AML): •20% blasts in bone marrow or peripheral blood. •Presence of Auer rods and granules 🧫. •Subtypes: •APL (M3): Multiple Auer rods, bundles (“faggot cells”), t(15;17). •Myelomonocytic (M4): Mix of myeloid and monocytic blasts. •Monocytic (M5): Prominent monoblasts with vacuoles. •Acute Lymphoblastic Leukemia (ALL): •Small, round blasts with scant cytoplasm. •B-ALL: Common in kids 👶, CD10 , CD19 . •T-ALL: Often presents with a mediastinal mass 🚩, CD3 , TdT . •Chronic Myeloid Leukemia (CML): •Hypercellular marrow with granulocytic hyperplasia 📊. •Increased neutrophils, myelocytes, basophils. •Look for blasts in advanced or blast phase. •Chronic Lymphocytic Leukemia (CLL): •Small lymphocytes with clumped chromatin. •Smudge cells: A hallmark on peripheral smear 💔. •Often co-expresses CD19/CD5. 📝 Mnemonic: •“AML = Auer Rods” •“ALL = A Little Lymphoblast” •“CML = Crowded Marrow” •“CLL = Clumped Chromatin” 4️⃣ Special Stains & Markers 🎨 •Cytochemical Stains: •MPO: Positive in myeloid blasts ✅. •Sudan Black B: Stains lipids in myeloid cells 🖤. •PAS: Positive in lymphoblasts 🟣. •Immunohistochemistry (IHC): •Blasts: CD34, CD117. •Lymphoblasts: TdT 🧬. •B-cell Markers: CD19, CD20. •T-cell Markers: CD3, CD7. •Flow Cytometry: •AML: CD13, CD33, CD34 . •B-ALL: CD19, CD10, TdT . •T-ALL: CD3, CD7, TdT . •CLL: CD19, CD5 co-expression. 📝 Mnemonic: “MPO = Myeloid, TdT = Tiny Lymphoblasts.” 5️⃣ Correlate with Clinical Data 📋 •Peripheral Smear: Check for circulating blasts, neutrophils, lymphocytes, or dysplastic cells. •CBC Trends: •WBC 📈 in CML or leukemic phases. •Pancytopenia in advanced marrow infiltration 🔻. •Cytogenetics: •AML: t(8;21), t(15;17) (APL), inv(16). •ALL: t(12;21) (good prognosis), t(9;22) (poor). •CML: t(9;22) (BCR-ABL). 💡 Tip: Clinical age helps: •ALL = Pediatric 👶. •AML = Elderly 👵. 6️⃣ Exam Pearls 📚 •AML Auer rods DIC: Think APL, start ATRA 🚑. •ALL mediastinal mass: T-ALL 🚩. •CML splenomegaly: Confirm with BCR-ABL 🧬. •CLL smudge cells: Classic feature 💔. •High WBC Basophilia: Often CML 📈. Key Summary for Slide Reading: FeatureAML 🧫ALL 🟣CML 📊CLL 💔 BlastsLarge, Auer rodsSmall, roundFew in chronic phaseAbsent MarkersMPO, CD33TdT, CD10, CD19BCR-ABLCD19/CD5 HallmarkAuer rodsMediastinal mass (T)↑ BasophilsSmudge cells For more pathology guidance, bookmark this thread! 🔬🩺 #Hematopathology #Leukemia #SlideReview

Going to USCAP? Visit @Roche at booth #228. Sign up to attend slide review or educational sessions. go.roche.com/USCAP2023-Twitt… #roche #USCAP2023 #slidereview #educational #conference #pathology #PathTwitter #SESSION

Going to USCAP? Visit @Roche at booth #228. Sign up to attend slide review or educational sessions. go.roche.com/USCAP2023-Twitt… #roche #uscap #slidereview #educational #conference #pathology #PathTwitter #session

What did you think of the latest episode of #SlideReview? Hoping to do something similar this week as I am currently offsite, which can make a live webinar more challenging. Let me know your thoughts! #GUPath Slides: bit.ly/SlideReviewGU04b Video: bit.ly/SlideReviewGU04

Thanks everyone for your patience - a new #SlideReview is now LIVE! The final chapter of our first #GUpath series can be found at the link below! #ChallengeCases coming out later this week! Slides; bit.ly/SlideReviewGU04b Video: bit.ly/SlideReviewGU04

#SlideReview @KMirza @ALBoothMD @mydermpath @JMGardnerMD @Williamson_SR @SaraEWobker @priyaraomd @LiangChengMD @AkgulMd @slusagar @pembeoltulu @rovingatuscap @Teclis82 @RoncinMD @Dr_Brian_Cox @anueru432 @arshna101 @RabailRai @mingfei_yan @OsmeAbdullah bit.ly/SlideReviewGU04

Missing your dose of #GUpath #SlideReview? Check out the #ShortReview on a bladder biopsy with a component of Small Cell Carcinoma at the link below! #VirtualPath Video: bit.ly/ShortReviewSmCCBladde… We'll be back next week with new content - thanks everyone for your patience 🙏

Anyone else missing their weekly dose of #SlideReview? On my last week of #coagulation, which has been great but definitely taking far more time than I’m used to! Hang on for one more week so that we can finish up the #GUpath series and dive into #GYNpath! #VirtualPath

Some days you just have to learn when to slow down. Today is one of those days - loving my #Coagulation rotation but it’s definitely keeping me on my toes! Because of this, there will be a special edition of #SlideReview this week...

Tonight on #SlideReview we'll be completing our #GUpath series with prostate and testicular lesions. Want to join the live Zoom (5:30pm EST)? bit.ly/SlideReviewZoom Joining Manually? Meeting # 734 1168 1509 PASSWORD CHANGES WEEKLY. PLEASE DM PRIOR TO 5:15PM EST TODAY

New #SlideReview is LIVE! Check out our bladder lecture (links below) #ChallengeCases out Friday! #GUpath #VirtualPath @KMirza @ALBoothMD @mydermpath @JMGardnerMD @Williamson_SR @LiangChengMD @SaraEWobker @RoncinMD Slides: bit.ly/SlideReviewGU03b Lecture: bit.ly/SlideReviewGU03

Tomorrow on #SlideReview we'll be completing our #GUpath series with prostate and testicular lesions. Want to join the session tomorrow (5:30pm EST)? bit.ly/SlideReviewZoom Joining Manually? Meeting # 734 1168 1509 PASSWORD CHANGES WEEKLY. PLEASE DM PRIOR TO 5:15PM EST WEDS

Tonight on #SlideReview we'll be continuing our #GUpath series with lesions involving the bladder. Want to join the live Zoom (5:30pm EST)? bit.ly/SlideReviewZoom Joining Manually? Meeting # 734 1168 1509 PASSWORD WILL BE CHANGING WEEKLY. PLEASE DM PRIOR TO 5:15PM EST

New #SlideReview is LIVE! Please see the links👇🏻for part 2 of our kidney lesions #GUpath #VirtualPath #ChallengeCases coming your way on Friday! Slides: bit.ly/SlideReviewGU02b Video: bit.ly/SlideReviewGU02

Almost ready to start #SlideReview! Part 2 of the #GUpath series (and part 2 of renal lesions) Want to join the live Zoom (5:30pm EST)? bit.ly/SlideReviewZoom Joining Manually? Meeting # 734 1168 1509 Password: 4VxhpN

Tonight on #SlideReview we'll be going back to our #GUpath series for a second helping of renal lesions! Want to join the live Zoom (5:30pm EST)? bit.ly/SlideReviewZoom Joining Manually? Meeting # 734 1168 1509 Password: 4VxhpN

New #ChallengeCases for #GUpath 01 is LIVE! Please give a watch/like/share (and sub) #VirtualPath #SlideReview @KMirza @ALBoothMD @mydermpath @Teclis82 @AkgulMd @slusagar @Williamson_SR @LiangChengMD @RoncinMD @mingfei_yan @ArshnaQ @RabailRai @anueru432 bit.ly/SlideReviewGU01c

Great example of a rare case (anyone recognize the features from this week’s #SlideReview?) #GUpath

New #SlideReview is LIVE! Part 1 of #GUpath - Kidney lesions. Please give a watch/like/share (and sub) #VirtualPath @KMirza @ALBoothMD @mydermpath @Teclis82 @AkgulMd @slusagar @Williamson_SR @LiangChengMD @RoncinMD Slides: bit.ly/SlideReviewGU01b Video: bit.ly/SlideReviewGU01

New #SlideReview is LIVE! The last video for the #GIpath series covers malignant colon/appendix lesions #VirtualPath @KMirza @ALBoothMD @mydermpath @CArnold_GI @JMGardnerMD @Teclis82 @ArshnaQ @RabailRai @anueru432 Slides: bit.ly/SlideReviewGI04b Video: bit.ly/SlideReviewGI04