This video features a pathology review of a tissue specimen, described as "cotton candy colored" due to its pinkish-purplish hue, with a multi-nodular architecture. The discussion centers on identifying two primary cell populations characteristic of a myofibroma. One population consists of bland, spindle to oval cells arranged in fascicles, often compressed between prominent, dilated, branching, interconnected vessels (sometimes called staghorn or hemangioparasitic vessels). The second population forms the nodules, which are described as exhibiting a bluish, mixoid/chondromyxoid appearance, leading the speaker to term them "pseudo chondroid nodules." While the cells are generally bland, mitotic activity can be present in the cellular areas between nodules. Myofibromas are classically seen in babies and children, are usually benign and indolent (sometimes regressing spontaneously), though rare, numerous visceral lesions can be problematic. The diagnosis is typically made definitively on H&E staining.
Pathology Review of a Classic Myofibroma
0:00 Specimen Description: The tissue sample is noted for its "cotton candy colored" appearance (pinkish-purplish/lavender) and distinct multi-nodular structure.
0:38 Biphasic Populations: The specimen shows two distinct cell populations:
Spindle/Oval Cells: Bland, somewhat plump cells arranged in fascicles, compressed between prominent, dilated, branching vessels.
Nodules: Formed by cells exhibiting a bluish, mixoid/chondromyxoid appearance, termed "pseudo chondroid nodules."
1:40 Vascular Pattern: The vessels are prominent, dilated, and branching, resembling a staghorn or hemangioparasitic pattern, common in various tumors but present here.
2:21 Clues for Diagnosis: The cellular areas show cells "bulging" or growing into the vessel lumens, a helpful diagnostic clue.
2:40 Diagnosis: Myofibroma: The classic findings lead to the diagnosis of myofibroma. The cells are myofibroblastic (positive for actin, usually negative for desmin).
3:07 Classic Presentation: The lesion features the large nodules (myoid/pseudo chondroid nodules) and the inter-nodular cellular areas containing prominent vessels.
3:57 Mitotic Activity: Mitotic activity can be seen in the cellular areas, but the cells remain generally bland and monotonous, lacking significant pleomorphism.
4:09 Clinical Relevance: Myofibromas are classically seen in babies and children. They are typically benign and indolent, often regressing spontaneously or not recurring after excision.
4:18 Rare Complications: Rarely, patients can have numerous lesions involving internal organs, which can cause problems or, in extremely rare cases, be fatal.
5:19 Other Features: The lesions can develop focal calcifications or even metaplastic bone.
5:32 Diagnosis Method: The diagnosis is usually made definitively based on the classic appearance on standard H&E staining without needing special stains.