Makindo Medical Notes

Mastocytosis is a rare mast cell disease affecting children and adults. It results from the accumulation of functionally defective mast cells (mastocytes) and CD34+ mast cell precursors in various tissues.

About

• Systemic Mastocytosis: A type of mastocytosis that impacts multiple organ systems.
• Classification: Recognized as a myeloproliferative neoplasm.

Aetiology

• Clonal Mast Cell Proliferation: Involves the pathological accumulation of mast cells in:
  • Skin
  • Bone marrow
  • Gastrointestinal (GI) tract
  • Spleen
  • Liver

Clinical Features

• Anaemia, bleeding tendencies, and lymphadenopathy (swollen lymph nodes).
• Urticaria Pigmentosa: A common skin manifestation, characterized by pigmented lesions.
• Symptoms such as itching, flushing, and tachycardia (rapid heartbeat).
• Abdominal pain, diarrhoea, and syncope (fainting).

Investigations

• Total Serum Tryptase: Persistent elevation (> 20 ng/mL) indicates mast cell activation.
• Imaging:
  • CT scan of the chest, abdomen, and pelvis to identify organ involvement or tumours.
  • Bone CT scans for evaluating suspected bone lesions.
• Biopsy:
  • Bone marrow aspiration and biopsy to confirm systemic involvement.
  • Liver biopsy to assess for mast cell infiltration in cases of organ dysfunction.
  • Skin biopsy to diagnose cutaneous manifestations like urticaria pigmentosa.

Management

• Acute Anaphylaxis: Immediate treatment following established anaphylaxis protocols.
• Corticosteroids: Useful for managing ascites, bone pain, and preventing severe allergic reactions.
• Osteopenia: Cases unresponsive to standard treatment may benefit from interferon alfa-2b.
• Symptomatic Treatment:
  • Antihistamines for controlling pruritus and flushing (H1 blockers).
  • H2 blockers and proton pump inhibitors (PPIs) to manage gastric hypersecretion and prevent peptic ulcers.
• Additional Therapies:
  • Aspirin to prevent vascular collapse (used with caution).
  • Mast cell stabilizers to alleviate pruritus and improve healing.
  • Leukotriene antagonists for symptom control.
  • Cromolyn sodium to reduce bone pain, headaches, and improve cutaneous symptoms.

Chemotherapy

• Limited Success: Chemotherapeutic agents with varying efficacy include:
  • Interferon-alfa
  • 2-Chlorodeoxyadenosine
  • Thalidomide
• Targeted Therapy: Imatinib mesylate is effective in patients with the wild-type KIT gene or the FIP1L1-PDGFRA rearrangement.

Conclusion

Mastocytosis is a complex and rare disorder with systemic and cutaneous manifestations. Accurate diagnosis requires clinical evaluation, laboratory tests, and imaging. Management focuses on symptomatic relief, prevention of complications, and targeted therapies for specific genetic mutations.