Table of Contents
Definition / general | Clinical features | Poor prognostic factors | Case reports | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Electron microscopy descriptionCite this page: Gulwani H. Parathyroid carcinoma of thymus. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/mediastinumPTH.html. Accessed December 9th, 2019.
Definition / general
- May arise within thymus or adjacent soft tissue of anterosuperior mediastinum
Clinical features
- Usually extreme hypercalcemia (> 14 mg/dl), markedly elevated parathyroid hormone (PTH) levels
Poor prognostic factors
- > 5 MF/HPF, thick fibrous capsule or infiltrative growth pattern
Case reports
- 33 year old man with postoperative hungry bone syndrome (Endocr Pract 2003;9:152)
- Hemodialysis patient with unusual thymic involvement (J Laryngol Otol 2004;118:162)
Gross description
- Resembles primary thymic carcinoma
- May invade adjacent lung, pericardium, thoracic great vessels
- Unencapsulated
Microscopic (histologic) description
- Modest to marked atypia
- Sheets, nests or cords of polyhedral cells with round / oval hyperchromatic nuclei, occasional nucleoli, clear / granular cytoplasm
- Focal mitotic activity, necrosis
- May have internal collagenous bands
Positive stains
- Diastase sensitive, PAS+, PTH (mosaic staining), variable chromogranin A or synaptophysin
Electron microscopy description
- Primitive intercellular junctional complexes, prominent cytoplasmic glycogen, primitive blunt microvilli, sparse neurosecretory granules
- No tonofilaments
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