Tc-99m sestamibi and In-111 DTPA octreotide uptake in breast carcinoma with neurendocrine differentiation.

Some breast tumors are classified as primary neuroendocrine carcinomas because of argyrophilia and positivity for neuroendocrine markers (chromogranins A and B and neuron-specific enolase), regardless of their cellular rest and cord structures. Tc-99m sestamibi has been widely used to identify epithelial breast carcinoma and lymph node metastases, whereas In-111 DTPA-octreotide has been used to identify primary and secondary neuroendocrine neoplasms specifically. The use of In-111 DTPA-octreotide and Tc-99m sestamibi scintigraphy in a woman with neuroendocrine differentiated cancer of the left breast is reported. Uptake of these radiopharmaceuticals only in the breast tumor permitted identification of a primary breast carcinoma, whereas absence of In-111 DTPA-octreotide uptake in other sites helped to exclude the presence of other neuroendocrine neoplasms in other organs.