# Clinical Cases: Myeloproliferative Neoplasms

## Case 1: Polycythemia Vera with Thrombosis

### Patient Presentation
**Demographics:** 58-year-old male

**Chief Complaint:** Headache, facial plethora, and pruritus after showers

**History of Present Illness:**
The patient has had progressive headaches and dizziness for 3 months. He noticed his face appears increasingly red. He reports intense itching after hot showers (aquagenic pruritus). Two weeks ago, he experienced transient vision loss in his right eye lasting 5 minutes. He also mentions burning pain in his fingers and toes.

**Past Medical History:**
- Hypertension
- No prior hematologic disease

**Physical Examination:**
- Blood pressure: 162/98 mmHg
- Heart rate: 78 bpm
- General: Ruddy, plethoric facies
- HEENT: Conjunctival injection
- Cardiac: Regular, no murmurs
- Abdomen: Splenomegaly (3 cm below costal margin)
- Extremities: Erythromelalgia (red, warm fingers with burning sensation)

### Workup and Results

**Laboratory Studies:**
- Hemoglobin: 19.8 g/dL
- Hematocrit: 59%
- WBC: 14,200/mcL
- Platelets: 485,000/mcL
- Erythropoietin: <1.0 mU/mL (suppressed)

**Molecular Testing:**
- **JAK2 V617F mutation: Positive**

**Bone Marrow Biopsy:**
- Hypercellular with trilineage hyperplasia
- Panmyelosis
- Clustered, enlarged megakaryocytes

### Clinical Image

![Polycythemia Vera](case_01_image.jpg)

*Facial photograph demonstrating plethoric (ruddy) appearance characteristic of polycythemia vera due to increased red cell mass, along with conjunctival injection.*

### Diagnosis
**Polycythemia Vera with Amaurosis Fugax (High-Risk)**

WHO 2016 Diagnostic Criteria Met:
- Major: Hemoglobin >16.5 g/dL (men)
- Major: Bone marrow panmyelosis
- Major: JAK2 V617F mutation
- Minor: Suppressed erythropoietin

High-risk features: Age >60, history of thrombosis (amaurosis fugax)

### Discussion
This case illustrates polycythemia vera:

- **JAK2 V617F Mutation**: The lecture states that JAK2 V617F is present in 95% of PV cases. This gain-of-function mutation causes constitutive activation of JAK2 signaling, leading to erythropoietin-independent erythropoiesis.

- **Suppressed EPO**: The lecture explains that serum erythropoietin is low/suppressed in PV, distinguishing it from secondary polycythemia where EPO is elevated (hypoxia, EPO-secreting tumors).

- **Aquagenic Pruritus**: The lecture describes this characteristic symptom triggered by warm water or showers. It's thought to be related to mast cell degranulation.

- **Thrombosis Risk**: The lecture emphasizes that thrombosis is the major cause of morbidity in PV. Both arterial (stroke, MI, amaurosis fugax) and venous (DVT, Budd-Chiari) events occur at increased rates.

### Treatment Plan
1. **Phlebotomy:**
   - Target hematocrit <45%
   - Continue until iron deficiency develops
   - CURE trial showed benefit of lower hematocrit target

2. **Low-Dose Aspirin:**
   - 81-100 mg daily (unless contraindicated)
   - Reduces thrombotic events

3. **Cytoreductive Therapy (High-Risk):**
   - Hydroxyurea first-line (500-1000 mg daily)
   - Target: Normalized counts and hematocrit <45%

4. **Management of Specific Symptoms:**
   - Erythromelalgia: Aspirin typically effective
   - Pruritus: Antihistamines, SSRIs, ruxolitinib if refractory

5. **Monitoring:**
   - CBC every 1-3 months
   - Watch for transformation to myelofibrosis or AML

### Teaching Points
1. JAK2 V617F is present in 95% of PV
2. Suppressed EPO distinguishes PV from secondary polycythemia
3. Target hematocrit is <45% (phlebotomy is cornerstone)
4. High-risk (age >60 OR prior thrombosis) requires cytoreduction
5. Transformation to myelofibrosis occurs in 15-20% at 15 years

---

## Case 2: Primary Myelofibrosis

### Patient Presentation
**Demographics:** 72-year-old female

**Chief Complaint:** Fatigue, early satiety, and night sweats

**History of Present Illness:**
The patient has had progressive fatigue for 6 months, requiring transfusions for symptomatic anemia. She reports early satiety after eating small amounts and left upper quadrant discomfort. She has night sweats and has lost 15 pounds unintentionally. She also notes easy bruising.

**Physical Examination:**
- Blood pressure: 118/72 mmHg
- Weight: 58 kg (down from 65 kg)
- General: Cachectic, pale
- Abdomen: **Massive splenomegaly** extending to pelvis (15 cm below costal margin)
- Hepatomegaly: 4 cm below right costal margin
- Ecchymoses on extremities

### Workup and Results

**Laboratory Studies:**
- Hemoglobin: 7.8 g/dL
- WBC: 4,200/mcL
- Platelets: 85,000/mcL
- LDH: 650 U/L (elevated)

**Peripheral Blood Smear:**
- **Tear-drop cells (dacrocytes)**
- **Leukoerythroblastosis** (nucleated RBCs, immature WBCs)
- Large, bizarre platelets

**Bone Marrow:**
- **"Dry tap"** on aspiration
- Biopsy: Marked reticulin and collagen fibrosis
- Megakaryocyte atypia with clustering
- CD34+ blasts: 3%

**Molecular Testing:**
- JAK2 V617F: Positive (60% of cases)

**DIPSS Score:**
- Age >65, Hgb <10, WBC >25K absent, blasts <1%, constitutional symptoms present
- Intermediate-2 risk

### Clinical Image

![Myelofibrosis Smear](case_01_image.jpg)

*Peripheral blood smear demonstrating characteristic findings of primary myelofibrosis: tear-drop cells (dacrocytes), nucleated red blood cells, and immature myeloid precursors (leukoerythroblastosis).*

### Diagnosis
**Primary Myelofibrosis, JAK2-positive, DIPSS Intermediate-2**

Diagnostic features:
- Bone marrow fibrosis with "dry tap"
- Leukoerythroblastic blood picture
- Tear-drop cells
- Massive splenomegaly from extramedullary hematopoiesis
- Constitutional symptoms

### Discussion
This case illustrates primary myelofibrosis:

- **Reactive Fibrosis**: The lecture clarifies that bone marrow fibrosis is reactive, not clonal - it results from cytokines released by megakaryocytes (particularly TGF-beta and PDGF).

- **Extramedullary Hematopoiesis**: The lecture explains that massive splenomegaly results from extramedullary hematopoiesis as the fibrotic marrow becomes inadequate. The spleen and liver resume fetal hematopoietic function.

- **"Dry Tap"**: The lecture identifies a "dry tap" on bone marrow aspiration as characteristic of myelofibrosis due to extensive fibrosis.

- **Leukoerythroblastosis**: The lecture describes the leukoerythroblastic blood picture (nucleated RBCs and immature WBCs) as reflecting disrupted marrow architecture releasing immature cells.

### Treatment Plan
1. **Transplant Evaluation:**
   - Only curative option
   - Consider if intermediate-2/high risk and eligible
   - Age and comorbidities limiting factors

2. **JAK Inhibitor (Symptomatic Relief):**
   - Ruxolitinib 15-20 mg twice daily
   - Reduces splenomegaly and constitutional symptoms
   - Does not cure disease or eliminate clone

3. **Anemia Management:**
   - Transfusion support
   - Consider erythropoietin-stimulating agents
   - Danazol may help some patients
   - Luspatercept in selected patients

4. **Splenectomy (Consideration):**
   - For refractory symptomatic splenomegaly
   - High surgical risk; reserved for select cases

5. **Monitoring:**
   - CBC monthly initially
   - Watch for blast transformation (5-30% risk)

### Teaching Points
1. Myelofibrosis causes "dry tap" on marrow aspiration
2. Tear-drop cells (dacrocytes) are characteristic
3. Leukoerythroblastosis = nucleated RBCs + immature WBCs
4. Massive splenomegaly is from extramedullary hematopoiesis
5. Allogeneic transplant is only curative treatment

---

## Case 3: Myelodysplastic Syndrome Transforming to AML

### Patient Presentation
**Demographics:** 68-year-old male

**Chief Complaint:** Worsening fatigue and new bruising

**History of Present Illness:**
The patient was diagnosed with MDS 2 years ago (MDS with ring sideroblasts) and has been monitored without treatment. He now presents with worsening fatigue, new petechiae, and gum bleeding. He reports fevers over the past week.

**Past Medical History:**
- MDS-RS diagnosed 2 years ago
- Baseline hemoglobin 9.5 g/dL, platelets 120,000/mcL

**Physical Examination:**
- Temperature: 38.4C
- Blood pressure: 110/68 mmHg
- General: Ill-appearing, pale
- Skin: Petechiae on lower extremities, ecchymoses on arms
- Oral mucosa: Gum bleeding
- No lymphadenopathy
- No hepatosplenomegaly

### Workup and Results

**Laboratory Studies (Current vs Baseline):**
- Hemoglobin: 6.8 g/dL (was 9.5)
- WBC: 1,200/mcL with ANC 300 (was 4,500)
- Platelets: 18,000/mcL (was 120,000)

**Peripheral Blood Smear:**
- Circulating blasts 8%
- Pseudo-Pelger-Huet cells
- Hypogranular neutrophils

**Bone Marrow Biopsy:**
- **25% blasts** (was 3% two years ago)
- Dysplasia in all lineages
- Ring sideroblasts still present (15%)
- Cytogenetics: Complex karyotype with del(7), del(5q)

### Clinical Image

![MDS to AML Transformation](case_01_image.jpg)

*Bone marrow aspirate demonstrating increased myeloblasts (>20%) indicating transformation from MDS to AML. Note the background dysplastic cells including hypolobated megakaryocytes.*

### Diagnosis
**AML with Myelodysplasia-Related Changes (Previously MDS-RS)**

Transformation criteria met:
- Blast count ≥20% (defines AML)
- Prior MDS history
- MDS-related cytogenetic abnormalities
- Multilineage dysplasia

### Discussion
This case illustrates MDS transformation:

- **Blast Threshold**: The lecture identifies 20% blasts as the threshold distinguishing MDS from AML. This patient's blasts increased from 3% to 25%, indicating transformation.

- **MDS Progression Risk**: The lecture notes that approximately 30% of MDS patients transform to AML. Higher-risk IPSS-R scores predict faster transformation.

- **TP53 and Complex Karyotype**: The lecture identifies complex karyotype and TP53 mutations as very poor prognostic factors associated with rapid transformation and treatment resistance.

- **Ineffective Hematopoiesis**: The lecture describes how MDS is characterized by ineffective hematopoiesis - the marrow is cellular but cells die prematurely (apoptosis), causing cytopenias despite adequate production.

### Treatment Plan
1. **Immediate Supportive Care:**
   - Transfusion support (pRBC, platelets)
   - Broad-spectrum antibiotics for febrile neutropenia
   - Growth factor support (G-CSF) if needed

2. **Treatment Decision:**
   - Intensive chemotherapy if fit and no prohibitive comorbidities
   - OR hypomethylating agent (azacitidine, decitabine) if not fit
   - OR venetoclax + azacitidine combination

3. **Transplant Evaluation:**
   - Allogeneic stem cell transplant consideration
   - Best long-term option if eligible

4. **Prognosis Discussion:**
   - AML arising from MDS has worse outcomes
   - Complex karyotype particularly poor
   - Goals of care discussion appropriate

### Teaching Points
1. 20% blasts = transformation from MDS to AML
2. ~30% of MDS patients transform to AML
3. Complex karyotype and TP53 mutations confer very poor prognosis
4. MDS is characterized by ineffective hematopoiesis (cytopenia despite cellular marrow)
5. Allogeneic transplant is potentially curative but limited by age/fitness

---

## Image Reference

For visual reference of MPN and MDS concepts, see:
- Radiopaedia: [Myelofibrosis](https://radiopaedia.org/articles/primary-myelofibrosis) - Imaging
- Wikipedia: [Polycythemia vera](https://en.wikipedia.org/wiki/Polycythemia_vera) - Clinical features
- Radiopaedia: [Myelodysplastic syndrome](https://radiopaedia.org/articles/myelodysplastic-syndrome) - Blood smear

---

## Learning Points

1. **JAK2 in PV**: Present in 95%; EPO is suppressed (distinguishes from secondary)

2. **PV Hematocrit Target**: <45% to reduce thrombosis risk

3. **Myelofibrosis Features**: Dry tap, tear-drop cells, leukoerythroblastosis, extramedullary hematopoiesis

4. **MDS to AML**: 20% blasts defines transformation; occurs in ~30% of MDS patients

5. **Only Cure**: Allogeneic transplant is only curative option for myelofibrosis and high-risk MDS/AML