Musculoskeletal and Skin Pathology for Medical II Students

Lab 1g Rhabdomyosarcoma, Alveolar Type (11000-89203)

Rhabdomyosarcomas are highly aggressive soft tissue tumors that predominantly affect children.  They are also the sarcomas that have responded best to improvements in radiotherapy and chemotherapy. As a group, rhabdomyosarcomas are the most common sarcomas in childhood, representing more than half such cases. Alveolar rhabdomyosarcoma is commonly located in an extremity where it is first seen as a rapidly growing mass. Grossly, it appears to arise from within muscle.

The diagnosis would be difficult without the use of modern immunopathological techniques such as use of peroxidase labeled antibodies to detect actin, a marker of skeletal muscle differentiation. 

Slides 19 & 20 | Slide 21

Slide 21 Examination of the area with excessive numbers of cells reveals that their nuclei vary in size and shape and in their chromatin patterns. Many of these cells have definite brown or tan staining of their cytoplasm. The normal striated muscle cells, the smooth muscle cells present in the walls of blood vessels and these atypical tumor cells all contain cytoplasmic actin by an  immuno-histochemical stain.

Digital Legends for Labs/Cases
Lab 1
1a | 1b | 1c | 1d | 1e | 1f | 1g
Gross & Radiographs
a | b | c | d | e | f | g | h 
Lab 2
2a | 2b | 2c | 2d | 2e | 2f

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Updated March 19, 2009