Objectives: This retrospective study was designed to present the clinical characteristics and histopathological features of Primary neuroendocrine carcinoma (PNEC) of breast, and to evaluate the impact on outcome following its management on the line of more common primary adenocarcinoma of breast.
Materials and methods: Records of four patients diagnosed with PNEC of breast were retrospectively reviewed. Data were obtained from medical record from January 2008 to December 2012. Diagnosis of PNEC was confirmed by histopathological examination (HPE) and immunohistochemical (IHC) staining of tissue obtained from Trucut biopsy of the breast lump in all four patients. PNEC of breast was defined by the presence of more than 50% of invasive tumor cells with cytoplasmic immunoreaction for neuroendocrine (NE) markers synaptophysin, chromogranin or neuron specific enolase as per WHO classification. All patients were treated with Modified Radical Mastectomy (MRM), six cycle of Cyclophosphamide, Adriamycin and 5-Flurouracil (CAF) based adjuvant chemotherapy, radiotherapy and hormonal therapy.
Results: There were four female patients. The mean age was 58~years (50-65 years). Breast lump was the presenting complaint in all patients. The result of HPE showed tumor size ranging from 4 to 6.5 cm in diameter. Axillary lymph node metastasis was detected in three (75%) patients. ER and PR expression was positive in four (100%) and three patients (75%) respectively. None of the patients expressed Her-2-neu. IHC staining was positive for NE markers chromogranin in three (75%) patients, synoptophysin in two patients (50%) and Neuron specific enolase three (75%) patients. The mean follow-up time was 27.7 months (range 48-9). All four patients survived without any loco-regional or metastatic recurrence with one patient developing lymphedema of arm.
Conclusions: Breast lump is the most common presentation of PNEC of the breast with characteristic expression of NE markers by the tumor. Management of this rare tumor may include surgery, chemotherapy, radiotherapy and hormonal therapy depending on the size of the tumor, lymph node and hormone receptor status. However, most appropriate treatment plan has yet to be established.
Keywords: Primary neuroendocrine carcinoma breast; breast lump; modified radical mastectomy.