Psammoma bodies ๐
Psammoma bodies are microscopic, round, concentrically laminated calcified structures seen in certain tumours and pathological conditions.
They are considered a diagnostic clue ๐ when identified on histology.
Characteristics ๐ฌ
- Structure:
- Concentric, lamellated โonion-skinโ calcifications.
- Round or oval; usually <100 ฮผm in diameter.
- Composition:
- Primarily calcium deposits.
- Form around a central nidus โ progressive mineral layering.
Pathological Significance โ ๏ธ
- Classically associated tumours:
- ๐ฆ Papillary thyroid carcinoma.
- ๐ฉโ๐ฆฐ Serous papillary ovarian carcinoma.
- ๐ง Meningioma.
- ๐ซ Mesothelioma.
- ๐ฉบ Papillary renal cell carcinoma.
- Other conditions:
- Endometrial carcinoma.
- Occasionally in benign processes (e.g., endosalpingiosis).
Diagnostic Importance ๐
- 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 โ๏ธ
- 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 ๐งพ
- Papillary Thyroid Carcinoma ๐ฆ: Psammoma bodies are a characteristic and diagnostic feature.
- Serous Papillary Ovarian Carcinoma ๐ฉโ๐ฆฐ: Commonly present, aiding histological diagnosis.
- Meningioma ๐ง : Frequently contains psammoma bodies, especially in the โpsammomatous meningiomaโ subtype.
Summary โจ
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: โPSaMMomaโ = Papillary thyroid, Serous ovarian, Meningioma, Mesothelioma.
