Orbital lymphoid neoplasms: Immunohistochemical patterns correlated with histopathological and clinical aspects

Abstract

Twenty-seven cases of orbital and adnexal lymphoid proliferation were reviewed in order to correlate histological findings with immunohistological patterns, the latter assessed by means of the immunoperoxidase method (PAP). Eight of the 27 biopsies were diagnosed, from the first biopsy, as low-grade malignancy lymphomas according to the Kiel classification. All these cases were immunologically monoclonal proliferations, because of the presence of cells bearing a single light chain or/and a single heavy chain. Lymphomas of the same type might have different levels of positivity. Nineteen of the 27 cases were pseudolymphomas, divided into two groups: reactive lymphoid hyperplasia (17 cases) and ‘atypical’ lymphoid hyperplasia (two cases). In all cases, with two exceptions, there was a polytypic Ig pattern.

The exceptions consisted of two cases diagnosed as ‘atypical’ lymphoid hyperplasia, where the immunohistological patterns were not clearly indicative of polyclonality. The two patients developed a malignant lymphoma according to a subsequent biopsy after an interval of one month and of 24 months, respectively. A third case that later on transformed into lymphoma was characterized in the first biopsy by a polyclonal pattern. Based on these results, the possibility has to be considered that orbital lymphoma can be suspected in cases histologically characterized by lymphoid proliferations of a mono-typic or even of a not clearly polytypic immunoglobulin pattern.

Key Words:

• orbital lymphoid neoplasms
• pseudotumors
• lymphomas
• histopathology
• immunohis-tochemistry
• clinical events