PMC3223957_01
Case 1. Microscopy of the resected tumour in patient 1. Well-differentiated neuroendocrine tumour arising within a tailgut cyst exhibiting a thick, fibrous wall (A) containing residual, disarrayed smooth muscle fibres (A, inset). Tumour cells showed a trabecular pattern of growth (B), diffuse immunoreactivity for synaptophysin (C) but only focal for chromogranin A (C, inset) and a low Ki-67 labelling index (less than 2%) (D).
can-5-201f1.jpg
PMC3223957_01_can-5-201f1.jpg
f1-can-5-201
The patient received no medical therapy and after a follow-up of 25 months, is in good clinical condition with no clinical, biochemical or radiological signs of recurrence (Figure 1).
PMC3223957_02
Case 2. Histological appearance of the resected tumour in patient 2. Well-differentiated neuroendocrine tumour arising within a tailgut cyst exhibiting a trabecular pattern of growth (A,B) with a residual component of disarrayed smooth muscle fibres (A, inset). Tumour cells were associated with residual glandular epithelium of tailgut cysts (B, inset) and showed faint to moderate immunoreactivity for chromogranin A (C) and a higher Ki-67 labelling index with 18% tumour cells being positive (D).
can-5-201f2.jpg
PMC3223957_02_can-5-201f2.jpg
f2-can-5-201
On the basis of the clinical, morphological and immunohistochemical findings, a clinically malignant, presacral carcinoid with liver metastases was diagnosed (Figure 2).