Learning Objectives
Identify the structural characteristics of Psammoma bodies as a form of dystrophic calcification. Master the differential diagnosis of tumors associated with these laminated spherules using the PSaMMOMa mnemonic, and recognize their characteristic basophilic appearance on H&E staining.
1. Morphology and Histology
Psammoma bodies are concentrically laminated, calcified spherules. They represent a specialized form of dystrophic calcification, where calcium salts deposit in layers around a focus of necrotic or degenerating cells.
| Feature | Description |
|---|---|
| Structure | Laminated (ring-like) calcified circles. |
| Staining | Deeply basophilic (purple/blue) on H&E due to calcium content. |
| Mechanism | Dystrophic calcification (occurs in the presence of normal serum  ). |
Activity:
2. Clinical Associations (The Mnemonic)
Psammoma bodies are high-yield markers for specific malignancies and benign tumors. Use the classic mnemonic PSaMMOMa to remember the primary associations:
| Letter | Condition | Key Context |
|---|---|---|
| P | Papillary carcinoma | Thyroid (most common) and Renal cell carcinoma. |
| S | Somatostatinoma | Pancreatic/Duodenal endocrine tumor. |
| M | Meningioma | Benign CNS tumor. |
| M | Mesothelioma | Linked to asbestos exposure. |
| O | Ovarian serous papillary | Cystadenocarcinoma. |
| M | Milk (Prolactinoma) | Pituitary adenoma. |
Activity:
High-Yield Mnemonics & Tips:
- Sand-Like: The word comes from the Greek psammos, meaning sand. Grossly, these calcifications can feel gritty.
- Thyroid Connection: If a biopsy of a thyroid nodule shows psammoma bodies, think Papillary Thyroid Cancer (look for Orphan Annie eyes nuclei too!).
- Meningioma: These are often incidental findings in meningiomas and are a classic feature of the “psammomatous” subtype.