MUCINOUS CARCINOMA OF THE BREAST - A CLINICOPATHOLOGICAL, HISTOCHEMICAL, AND IMMUNOCYTOCHEMICAL STUDY WITH SPECIAL REFERENCE TO NEUROENDOCRINE DIFFERENTIATION

We studied the clinical, histologic, histochemical, and immunocytochem ical characteristics of 61 mucinous tumors (38 pure, 23 mixed) retriev ed from a consecutive series of 1,689 infiltrating carcinomas of the f emale breast. The only statistically significant predictors of favorab le survival were histologic (pure) type coupled with the absence of ax illary lymph node metastases. Other factors, including classification into A and B types according to Capella et al., and neuroendocrine sta tus, as assessed by the presence of argyrophilia, granins, neuron-spec ific enolase (NSE), and synaptophysin (SYN),-all had no influence on s urvival. Argyrophilic cells were found in 16 pure mucinous tumors (42% ) and in the mucinous component of four mixed tumors (17%). Granin (ch romogranin A or B), NSE, and SYN immunoreactivities were demonstrated in all the argyrophilic tumors. We also found NSE- and SYN-immunoreact ive cells in 31 of 41 and 16 of 41 nonargyrophilic (granin-unreactive) mucinous tumors, which supports the view that mucinous carcinomas of the breast as a whole are neuroendocrine-programmed tumors.