Meshari Almotairi

Physician, Stream 2 graduate 👨🏽‍🎓👨🏾‍⚕️🔬 @uidaho @wsuPullman @ksau_hs Currently a #Hematopathology resident at @kfshrc

[TigerHemePath @Tiger_heme]

Easy case, for trainees. Make a diagnosis without H&E 🙃 IgD, CD21, OCT2, MEF2B. Did you get it right? Check the comments

[Kathryn Lindsey @PathologyKate]

Apparently you can have Reed-Sternberg like cells in Follicular lymphoma!? The immunostain is CD30!

[Neil Stone @DrNeilStone]

Hepatitis C used to mean cirrhosis, cancer, liver transplant.

Now it's 8–12 weeks of tablets and a cure rate over 95%.

Science did that.

[التواصل الحكومي @CGCSaudi]

قصة بدأت بمرض نادر، وفقدان إخوة، وسنوات من المعاناة.. وانتهت بعلاج جيني منحه الوطن ليبدأ فصلًا جديدًا من الحياة. @KFSHRC

[Tania Labiano @tlabiano]

🧠💧Cerebrospinal fluid #CSF #cytology 🔬Large cells w/ pleomorphic population of lymphoid cells with irregular nuclear contours.
📋✍🏼Patient has history of Diffuse large B-cell lymphoma.
#giemsa #cytopath

[Meredith Herman, DO @MeredithKHerman]

Something’s brewing in the bone marrow…
Don’t Tryp on these mast cells!

A spindling review of systemic mastocytosis:

🚨Atypical= Spindled
🔴Cluster > 15 cells
🦴Para trabecular/perivascular
🧪CD2+ CD25+ Tryptase+
🧬KIT D816V

#hemepath #PathX #ABPath

[Benlazar S M A @smbenlazar]

Morphological characterization of acute myeloid leukaemia with t(11;17)(q23;q21)/ZBTB16::RARA fusion https://t.co/0CXtPO9t0L

[Sa A Wang, MD @SaWangMD]

Jessie Xu: nodal based T/NK lymphoma. From flow you can guess the diagnosis

[Meshari Almotairi @mesharisolari]

@bedi_begui Do you routinely perform p53 IHC on all MCL cases?

[Beatriz Agredano🐻����🐻‍❄️ @bedi_begui]

Mantle cell lymphoma in a bone marrow biopsy. I love it when things work out well!
#pathology #hemepath👩‍🔬🩸

[Dr Ihab Suliman @IhabFathiSulima]

A characteristic “tennis-racket” cytoplasmic organelle is identified on electron microscopy.

In which condition is this finding classically seen?

A. Malignant histiocytosis
B. Langerhans cell histiocytosis
C. Juvenile xanthogranuloma
D. Niemann–Pick disease

[Benlazar S M A @smbenlazar]

Cuplike nuclei and bimodal CD34 expression in adult KMT2A-rearranged pro-B acute lymphoblastic leukemia https://t.co/cSQGBKAAoO

[Benlazar S M A @smbenlazar]

Niemann–Pick disease | ASH Image Bank | American Society of Hematology https://t.co/hX7hJ8yCPN #ASHImageBank

[Bread & Butter Haematology @MorphologyAmigo]

Haembyte

High Grade Lymphomas .......
How to tell them apart in a simple way....
May come in Handy for Upcoming FRCPath- You never know 😀
#medicine #medtwitter #meded #blooducation #hematology

[Papa Heme @Papa_Heme]

The CHIP/CCUS field is becoming the new MGUS. Stop ordering NGS on all mild cytopenias. Follow them for a few months. If it’s worse than do what you want.

[Dr. Chokri Ben Lamine @abouabdrahman0]

💊🧬 “Lenalidomide” in hematology — small capsule, major impact

🎯 Key roles:
🔹 Multiple myeloma: induction and maintenance
🔹 Selected lower-risk del(5q) MDS
🔹 R² with rituximab in selected indolent lymphomas

⚙️ Mechanism: binds cereblon → degradation of IKZF1/IKZF3 → antitumour and immunomodulatory effects.

⚠️ Remember:
🩸 Cytopenias → monitor CBC
🫁 VTE/arterial thrombosis → risk-adapted prophylaxis
🧴 Rash | 🦠 infections | 🚽 diarrhoea
🫘 Adjust dose for renal function
🚫 Teratogenic—strict pregnancy-prevention measures

🧬 Secondary malignancies are a recognised long-term signal, historically strongest with lenalidomide plus oral melphalan. This requires surveillance and counselling—but, for appropriate patients, the therapeutic benefit generally outweighs the risk.

📚 Revlimid clinical information | IMWG thrombosis guidance | SPM meta-analysis

#Hematology #MultipleMyeloma #MDS #Lymphoma #Lenalidomide 💊🩸

[Dr. Chokri Ben Lamine @abouabdrahman0]

🩸 Red-Cell Antigen Phenotyping: How to Interpret It

🔬 Antigen phenotyping determines which inherited antigens are present (+) or absent (−) on the patient’s red blood cells.

🧬 Major systems commonly tested:
🔴 Rh: C, c, E, e
🟠 Kell: K, k
🟡 Duffy: Fya, Fyb
🟢 Kidd: Jka, Jkb
🔵 MNS: M, N, S, s

✅ Positive antigen = expressed on the RBCs
❌ Negative antigen = absent; the patient may form an alloantibody against it after exposure through transfusion or pregnancy.

⚠️ Examples:
E− → risk of developing anti-E
K− → risk of developing anti-K
Fya− → risk of developing anti-Fya
Jka− → risk of developing anti-Jka

🩺 Why is phenotyping important?

🩸 Investigating or preventing RBC alloimmunization
🎯 Selecting antigen-negative compatible units
♻️ Supporting chronically transfused patients
🔎 Interpreting complex antibody panels
🛡️ Preventing delayed hemolytic transfusion reactions
🤰 Assessing antibodies relevant to hemolytic disease of the fetus and newborn

🌍 Special example: Fy(a−b−)

This is the Duffy-null phenotype, common among individuals of African and Middle Eastern ancestry.

🧪 It may be associated with a persistently lower circulating absolute neutrophil count—now called Duffy-null–associated neutrophil count (DANC).

✅ Usually no increased infection risk
✅ Does not require treatment by itself
⚠️ Diagnose only after clinical correlation and exclusion of other relevant causes of neutropenia.

🚨 Important limitations

🩸 Phenotyping may be unreliable following recent transfusion because circulating donor RBCs can produce mixed results.
🧪 A positive direct antiglobulin test may also interfere with serologic testing.
🧬 RBC genotyping is preferable when recently transfused, DAT-positive, extensively alloimmunized, or when serologic findings are inconclusive.

📌 Phenotype tells us what is expressed on circulating RBCs; genotype predicts inherited antigen expression.

🔗 References:
American Society of Hematology—Duffy-null associated neutrophil count⁠
NCBI—Blood Groups and Red Cell Antigens⁠
Canadian Blood Services—Serological best practices⁠

#Hematology #TransfusionMedicine #BloodBank #DuffyNull #DANC

[Abdul Muqtadir Abbasi @AbbasiMuqtadir]

Anybody, any experience with Adzynma for congenital TTP? Any pros and cons. Personal experience?

For those who are not aware about Adzynma,

Adzynma (apadamtase alfa) is a recombinant enzyme replacement therapy used to treat both children and adults with congenital thrombotic thrombocytopenic purpura (cTTP), a rare inherited blood-clotting disorder. It replaces the missing ADAMTS13 enzyme to prevent harmful blood clots, low platelets, and anemia.

#cTTp #adzynma

Ps. There is no conflict of interest.

[Dr. Chokri Ben Lamine @abouabdrahman0]

🧵 Rosai–Dorfman–Destombes disease (RDD): hematology pearls

1️⃣ What is it?
A rare histiocytic neoplasm formerly called sinus histiocytosis with massive lymphadenopathy.
📌 Derived from activated macrophage-lineage histiocytes
📌 Usually indolent, but behavior ranges from spontaneous remission to organ-threatening disease.

2️⃣ Classic presentation

👤 Children or young adults—although any age is possible
🦒 Massive, painless, bilateral cervical lymphadenopathy
🌡️ Fever, night sweats or weight loss
🩸 Neutrophilia, anemia, raised ESR/CRP
🧪 Polyclonal hypergammaglobulinemia

3️⃣ Extranodal disease

Occurs in approximately 40% of patients:

🩹 Skin—most frequent extranodal site
👃 Nasal cavity/sinuses
👁️ Orbit
🦴 Bone
🧠 Dural/CNS masses mimicking meningioma
🫁 Airways/lung
🫘 Kidney
🧬 Salivary gland, breast, testes and soft tissue

⚠️ Airway, CNS, orbital, renal or multiorgan disease may become organ-threatening.

4️⃣ Pathology hallmark

🔬 Large pale histiocytes showing emperipolesis: intact lymphocytes, plasma cells or neutrophils within the histiocyte cytoplasm without destruction.

Immunophenotype:
✅ S100 positive
✅ CD68/CD163 positive
✅ OCT2 and cyclin D1 frequently positive
❌ CD1a negative
❌ Langerin/CD207 negative

📌 Emperipolesis is supportive but not entirely specific—clinicopathological correlation is essential.

5️⃣ Molecular biology

🧬 Somatic MAPK-pathway alterations occur in a subset:

• KRAS
• NRAS
• MAP2K1
• ARAF
• CSF1R
• Rare BRAF alterations

➡️ Perform tissue next-generation sequencing in severe, refractory or disseminated disease because it may identify a target for MEK inhibition.

6️⃣ Clinical categories

🔵 Classical nodal RDD
🟣 Extranodal RDD
🧬 Familial RDD—consider SLC29A3-related disease
🛡️ Immune-associated RDD: SLE, autoimmune cytopenias or ALPS
🎗️ Neoplasia-associated RDD: may coexist with lymphoma, myeloid neoplasms or other cancers

7️⃣ Differential diagnosis

🔍 Langerhans-cell histiocytosis
🔍 Erdheim–Chester disease
🔍 Juvenile xanthogranuloma
🔍 Hodgkin/non-Hodgkin lymphoma
🔍 IgG4-related disease
🔍 Sarcoidosis
🔍 Tuberculosis or fungal infection
🔍 Metastatic carcinoma/melanoma
🔍 Hemophagocytic lymphohistiocytosis

⚠️ Increased IgG4-positive plasma cells alone do not establish IgG4-related disease.

8️⃣ Initial work-up

🧫 Core or excisional biopsy with expert hematopathology review
🩸 CBC, renal/liver profile, ESR/CRP and immunoglobulins
🛡️ Autoimmune testing when clinically indicated
📸 FDG-PET/CT or CT neck/chest/abdomen/pelvis
🧠 MRI for neurological, orbital or sinonasal disease
🧬 NGS for MAPK-pathway alterations
🦴 Bone marrow only for unexplained cytopenias or suspected marrow involvement

9️⃣ Who can be observed?

👀 Observation is appropriate for:

✅ Asymptomatic nodal or cutaneous disease
✅ Non-bulky disease without organ compromise
✅ Stable postoperative residual disease

Many cases remain stable or regress spontaneously. Reassess clinically and radiologically according to the involved sites.

🔟 When to treat?

🚨 Progressive or symptomatic disease
🚨 Vital-organ dysfunction
🚨 Airway obstruction
🚨 Neurological or visual compromise
🚨 Renal involvement
🚨 Severe autoimmune cytopenia
🚨 Multifocal/disseminated disease affecting quality of life

1️⃣1️⃣ Treatment approach

🔪 Surgery: preferred for isolated, accessible or compressive lesions; complete excision may be curative.

💊 Corticosteroids: prednisone approximately 40–70 mg/day followed by an individualized taper; responses may be transient.

☢️ Radiotherapy: selected unresectable, residual or critical-site disease.

🧪 Cladribine: 5 mg/m²/day IV for 5 days every 28 days, commonly for 3–6 cycles in severe or refractory systemic disease; monitor for prolonged myelosuppression and opportunistic infection.

Other selected options include low-dose methotrexate ± 6-mercaptopurine, sirolimus—particularly with immune dysregulation—and lenalidomide-based therapy.