Treatment

The lesion was biopsied under local anesthesia. The results of the incisional biopsy led to a referral to an oncologist for further treatment.

Incisional Biopsy

This case was diagnosed by Dr. Heike Deubner at Department of Pathology, Harborview Medical Center. We thank Dr. Deubner for the diagnosis and the histology photographs.

Histologic examination of the H & E section revealed sheets of small blue round cells representing atypical cells (Figure 3) which with higher magnification appeared to be atypical plasma cells with moderate nuclear pleomorphism, and prominent nucleoli (Figure 4). Mitotic figures were identified. Immunohistochemical stains were uniformly and strongly positive with CD138 and Kappa light chain and negative with Lambda light chain (Figure 5).

Figure 3 Low power (x40) H & E histology shows oral mucosa covered by epithelium and supported by connective tissue infiltrated by sheets of small round blue cells. The sheets of cells are denser at the bottom part of the connective tissue. We thank Dr. Deubner for the diagnosis and the histology photographs.

 

Figure 4 High power (x400) histology shows sheets of plasma cells, most are large and atypical with large nuclei and prominent nucleoli. Occasional normal and mature plasma cells are present. We thank Dr. Deubner for the diagnosis and the histology photographs.

Figure 5 High power (x400) immunohistochemistry for kappa, lambda and CD138. Note uniform paoitive staining with kappa light chain but negative with lambda. It is also uniformaly positive with CD138, a marker for plamacytoid cells. We thank Dr. Deubner for the diagnosis and the histology photographs.