Ectopic ACTH Syndrome Emerging 5 Years after the Diagnosis of Neuroendocrine Tumor

Figure 1

Histopathology and immunohistochemistry of metastatic NEC biopsy specimens: (a) Positive control: ACTH staining in normal pituitary tissue. Stained cells (red arrows) have brown cytoplasm. (b) Rare ACTH-positive cells in the subcarinal node that provided the initial diagnosis of NET and in (c) liver dome biopsied 3.5 years later. Increase in staining intensity and number of cells staining positive for ACTH in (d) shoulder mass and (e) pelvic mass, biopsied 4 and 4.5 years after initial diagnosis, respectively. (f) Positive control: AgRP staining in normal adrenal tissue. No staining for AgRP in specimens biopsied earlier in the disease course: (g) subcarinal node and (h) liver dome. Specimens biopsied later: (i) shoulder mass and (j) pelvic mass: show rare cells staining for AgRP.