Primary rhabdomyosarcoma: An extremely rare and aggressive variant of male breast cancer

Figure 1 Macroscopic features. A: Ulcerated rhabdomyosarcoma of the male breast; B: Tumor relapse, one month after mastectomy.

Figure 2 Histological features of a hybrid tumor of the breast. A and B: Major population, some of the cells showing rhabdomyoblastic differentiation (A) and atypical mitoses (B); C-E: Small cell population, demonstrating lobular architecture (C), with formation of rosette-like structures (D and E).

Figure 3 Immunohistochemical profile of major cell population. A: Vimentin diffuse positivity confirms the mesenchymal origin; B-D: The rhabdomyosarcomatous differentiation is confirmed by the positivity for desmin (B), myogenin (C) and sarcomeric actin (D).

Figure 4 Immunohistochemical profile of small cell population. A-C: The neuroectodermal origin is confirmed by the positivity for neurofilament (A), neuron specific enolase (B) and CD99 (C); D: CD56 positivity proves the interaction between myocytes and neural cells.