Congenital sacrococcygeal rhabdomyosarcoma

Abstract

Rhabdomyosarcoma (RMS) is one of the common malignant soft-tissue sarcomas affecting children. It originates from the embryonic mesenchyme precursor of striated muscle and is frequently seen in the head-and-neck region, genitourinary system and extremities. Occasionally, it arises from the retroperitoneum, biliary tract and abdomen and is rarely seen in the sacrococcygeal area. A 4-month-male child presented with a nodule over the sacrum. Based on histopathology and immunohistochemical marker studies, a final diagnosis of RMS was rendered. There was no evidence of any teratomatous elements.

Keywords: Congenital; desmin; immunohistochemistry; infants; rhabdomyosarcoma; sacrococcygeal tumour.

Figure 1

Gross: Circumscribed grey white lesion with multiple cystic areas

Figure 2

(a) Tumour shows round to oval cells in cellular solid patterns. (H and E × 100). (b) Tumour with cells in alveolar patterns and discohesive patterns. (H and E × 100)

Figure 3

(a) Cells showing uniform round nuclei with scant cytoplasm. (H and E × 400). (b) Rhabdomyoblasts with abundant eosinophilic cytoplasm and tadpole-like appearance and multinucleated giant cells with multiple peripherally placed nuclei (wreath-like nuclei). (H and E × 400)

Figure 4

(a) Tumour cells showing cytoplasmic positivity for desmin (immunohistochemistry × 100). (b) Cytoplasm of Rhabdomyoblasts and tumour giant cells positive for desmin (immunohistochemistry × 400)