Treatment

After the excisional biopsy, the patient was referred for systemic evaluation and treatment.

Excisional Biopsy

Histologic examination revealed multiple fragments of soft tissue with small associated fragments of bone infiltrated in a diffuse pattern by sheets of large atypical lymphoid cells with scant cytoplasm, round to irregular nuclei, vesicular chromatin, and prominent nucleoli (Figures 3 & 4). Mitotic figures are present and apoptotic debris is easily identified (Figure 4). The atypcial infiltrate involves skeletal muscle. The atypical cells are positive for CD20, BCL-6, BCL-2 (variable intensity of staining), and MUM-1 (variable, greater than 30% positive) with no convincing expression of CD5, CD10, cyclin D1, CD138, kappa or lambda. Approximately 60% of the atypical cells are Ki-67 positive.

Figure 3 High power (x200) H & E histology shows sheets of large atypical lymphoid cells with scant cytoplasm, round to irregular nuclei, vesicular chromatin, and prominent nucleoli. The atypcial cells infiltrated the nearby skeletal muscle bundles (not shown).

Figure 4 Higher power (x400) H & E histology with closer look at the sheets of large atypical lymphoid cells with scant cytoplasm, round to irregular nuclei, vesicular chromatin, prominent nucleoli and mitotic figures.