Interdigitating dendritic cell sarcoma of salivary gland associated lymphoid tissue not associated with HHV-8 or EBV infection

Abstract

Interdigitating dendritic cell sarcoma (IDCS) is an extremely rare malignancy derived from professional antigen presenting cells. This report describes a case of IDCS arising in the salivary gland associated lymphoid tissue of the parotid gland of a 51 year woman, presenting with a painless neck swelling. Histologically, sheets of S100(+)/Ccd68(+)/CD45(+)/CD34(-)/CD1a(-) spindle cells were surrounded with an inflammatory infiltrate with no evidence of B or T cell clonal proliferations. No evidence of either human herpesvirus 8 or Epstein-Barr virus could be detected by quantitative polymerase chain reaction in the tumour cells with serological evidence of previous Epstein-Barr virus infection. The patient remains well and disease free 24 months after presentation without specific treatment.

Figure 1

Extranodal interdigitating dendritic cell sarcoma. Sagital computerised tomographic image at the level of the mandible demonstrating a mass lesion in the inferior pole of the right parotid gland (arrow).

Figure 2

(A, B) Histological examination of the resected inferior pole of the right parotid gland. The central lymphoid area is replaced by a proliferation of large spindle shaped cells with large oval or round nuclei and prominent nucleoli (haematoxylin and eosin stain; original magnification: (A), ×400; (B), ×1000). (C, D) Immunohistochemical examination revealed the spindle cells to be S100⁺/CD45⁺/CD1a⁻/CD34⁻/CD3⁻/CD20⁻ (original magnification: (C), ×400; (D), ×1000).

Figure 3

Quantitative polymerase chain reaction analysis. The tumour DNA was amplifiable with β globin primers (triangles), but was negative for human herpesvirus 8 (HHV-8) genomes (circles; not crossing the threshold value, indicated by arrow). The amplification plot for the HHV-8 positive control is indicated by the squares.