Estrogen Receptor Determinations of Cutaneous Recurrences of Breast Cancers: Reduced Sensitivity of Hormone Binding Assays

Abstract

: Patients with estrogen receptor positive breast carcinoma occasionally develop cutaneous recurrences that apparently do not contain receptors when analyzed by the dextran coated charcoal method. Since these nodules may contain only a few tumor cells, we wondered if such negative results were accurate. Our study group consisted of 19 pairs of specimens, each pair comprising a cutaneous nodule and the primary tumor from which it arose. Estrogen receptor determinations using the dextran coated charcoal method had been performed on each cutaneous specimen, and we repeated these determinations using an immunohistochemical method. We then compared the data derived from the cutaneous specimens with the estrogen receptor status of the corresponding primary tumors. The dextran coated charcoal method failed to detect receptors in about 70% of the recurrences that arose from receptor positive tumors (10 of 14 cases). The immunohistochemical staining, on the other hand, detected estrogen receptor protein in all 14 of these cutaneous nodules. In six cases, the small number of tumor cells in the cutaneous specimens could explain the discrepancy between the results of the immunohistochemical staining and the hormone binding assay. Administration of tamoxifen probably accounts for the divergent results in one other case. In the final three cases, the discrepancies remain unexplained. We conclude that cutaneous recurrences of breast carcinoma display estrogen receptors about as frequently as do primary tumors, but that the dextran coated charcoal assay may not detect the receptors in some cutaneous specimens. Physicians should bear these observations in mind when they encounter a case in which an estrogen receptor positive tumor has apparently given rise to a receptor negative cutaneous recurrence. Immunohistochemical staining of the nodule might reveal the receptors in such a case.