Immunohistological studies in five patients with unknown primary carcinomas and poorly differentiated neoplasms

In the evaluation of five patients with unknown primary carcinomas or poorly differentiated neoplasms, the most critical step was to obtain an accurate histological diagnosis upon which to base therapeutic options and prognosis. This required a thorough pathological examination which included histochemical and immunohistological staining of a properly prepared biopsy specimen of ample size. Two cases of lymphoma, two of carcinoma, and one of melanoma are presented in which the correct pathological diagnosis was made with immunohistological techniques permitting the institution of appropriate therapy. The value of a simple antibody panel employed with properly prepared tissue is clearly demonstrated by these cases.