tumor pseudocapsule
Pronunciation: SOO-doh-cap-sool
A compressed layer of normal tissue and reactive fibrous material surrounding certain tumors, often mistaken for a true capsule.
Full Definition
A tumor pseudocapsule is a deceptive layer of compressed normal tissue, inflammatory cells, and reactive fibrous tissue that forms around certain malignant tumors, particularly sarcomas and some carcinomas. Unlike a true capsule, the pseudocapsule is not a reliable barrier to tumor spread and may contain microscopic tumor extensions or satellite lesions. Surgical dissection along the pseudocapsule plane, known as 'shelling out,' significantly increases the risk of positive margins and local recurrence. Proper oncologic resection requires excision beyond the pseudocapsule with a margin of normal tissue. Recognition of pseudocapsules is crucial for surgical planning and achieving adequate oncologic resection, particularly in soft tissue sarcomas where the pseudocapsule can be quite prominent.
Usage
Usage note: Emphasize that this is not a protective barrier; hyphenate when used as adjective.
In Context
- "The tumor pseudocapsule was carefully identified and excised with surrounding normal tissue." — Sarcoma operative report
- "Inadvertent violation of the tumor pseudocapsule occurred during dissection, requiring wider excision." — Surgical complication note