This pathology video focuses on a large, pedunculated Angiofibroma (also known as a Fibrous Papule), highlighting its unusual size compared to the common, small lesions found on the nose. The speaker details the microscopic features, including dilated vessels, dense collagen, plump spindle-to-stellate cells, and the presence of adnexal structures (hair follicles/sebaceous glands) which helps distinguish it from an acrochordon (skin tag). A key diagnostic pearl is presented: Angiofibroma should be the top differential for benign-appearing spindle cell lesions on the nose due to its variable morphology. The video also discusses secondary changes, like edema resulting from compromised lymphatic drainage in the pedunculated stalk, and reviews the syndromic associations, particularly Tuberous Sclerosis (in children with multiple lesions) and Birt-Hogg-Dubé syndrome (in adults).
Summarizing the Pathology of a Large Angiofibroma
0:00 Large Angiofibroma Identified: The specimen is identified as a large Angiofibroma (Fibrous Papule), noting its size is significantly larger than the typically seen tiny white bumps on the nose.
0:49 Histological Characteristics: Key features include dilated blood vessels, a dense collagen background, plump spindle-to-stellate cells, and the presence of epithelial structures like hair follicles and sebaceous glands (distinguishing it from conventional skin tags).
1:34 Diagnostic Pearl for Nasal Lesions: The speaker emphasizes that if a benign-looking spindle cell lesion is found on the nose of an adult, Angiofibroma should be the top differential diagnosis, as it can exhibit wide morphological variation (including pleomorphism, myxoid change, and sclerotic stroma).
2:37 Secondary Edema: This large, pedunculated specimen shows Edema due to the thin stalk likely causing impingement on lymphatic drainage, leading to localized lymphedema-like change, similar to observations in large acrochordon (skin tags).
3:11 Cell Morphology: The characteristic cells are described as stellate (star-shaped or triangular/spiky looking) cells, sometimes displaying bi- or tri-nucleation. A mnemonic relating the cell shape to the Star Trek Next Generation insignia is offered.
4:18 Syndromic Associations: Multiple Angiofibromas on the face of a child are highly associated with Tuberous Sclerosis (the historical term "adenoma sebaceum" is noted as a misnomer). Multiple fibrous papules in adults may suggest Birt-Hogg-Dubé syndrome.
4:42 Key Takeaway: The vast majority of fibrous papules encountered in practice are solitary, incidental lesions in adults, not related to these syndromes.