Makindo Medical Notes

Psammoma bodies are microscopic, round, concentrically laminated calcified structures seen in certain tumours and pathological conditions. They are considered a diagnostic clue 🔎 when identified on histology.

Characteristics 🔬

• Structure:
  • Concentric, lamellated “onion-skin” calcifications.
  • Round or oval; usually <100 μm in diameter.
• Composition:
  • Primarily calcium deposits.
  • Form around a central nidus → progressive mineral layering.

Pathological Significance ⚠️

• Classically associated tumours:
  • 🦋 Papillary thyroid carcinoma.
  • 👩‍🦰 Serous papillary ovarian carcinoma.
  • 🧠 Meningioma.
  • 🫁 Mesothelioma.
  • 🩺 Papillary renal cell carcinoma.
• Other conditions:
  • Endometrial carcinoma.
  • Occasionally in benign processes (e.g., endosalpingiosis).

Diagnostic Importance 🔎

• Histopathology:
  • Basophilic, concentric lamellated calcifications on H&E.
  • Easily recognised on routine light microscopy.
• Clinical relevance:
  • Serve as a useful diagnostic marker in papillary tumours.
  • Help differentiate tumour subtypes (e.g., papillary vs follicular thyroid carcinoma).

Mechanism of Formation ⚙️

• Cellular origin:
  • Arise from necrotic/apoptotic cells acting as a nidus for calcification.
  • Also form via calcification of degenerating papillary stalks.
• Inflammatory role: Chronic inflammation and cytokine release may promote calcium deposition.

Examples in Specific Tumours 🧾

• Papillary Thyroid Carcinoma 🦋: Psammoma bodies are a characteristic and diagnostic feature.
• Serous Papillary Ovarian Carcinoma 👩‍🦰: Commonly present, aiding histological diagnosis.
• Meningioma 🧠: Frequently contains psammoma bodies, especially in the “psammomatous meningioma” subtype.

Summary ✨

Psammoma bodies = concentric lamellated calcifications, most classically associated with papillary thyroid carcinoma, serous ovarian carcinoma, and meningioma. They are an important histopathological hallmark and can guide diagnosis towards papillary-patterned tumours. Remember the mnemonic: “PSaMMoma” = Papillary thyroid, Serous ovarian, Meningioma, Mesothelioma.