Anal canal adenocarcinoma with neuroendocrine features accompanying secondary extramammary Paget disease, successfully treated with modified FOLFOX6: a case report

Abstract

Background: Anal canal cancer occasionally accompanies extramammary Paget disease. Although most of them are squamous cell carcinoma, anal canal adenocarcinoma with neuroendocrine features accompanying secondary extramammary Paget disease has never been reported.

Case presentation: Here, we report a 76-year-old man presented with pruritus in the perianal area. Investigation revealed a fist-sized perianal erythema, diffuse liver tumors, and right inguinal lymph node swelling. Pathological examination of biopsies from the erythema suggested secondary extramammary Paget disease with positive cytokeratin-7 and -20 expressions and negative GCDFP-15 expression. The anal canal tumor was confirmed by digital examination and endoscopy. Biopsies from the anal canal tumor, swollen lymph node, and Paget lesion all showed poorly differentiated adenocarcinoma with neuroendocrine features expressing synaptophysin and chromogranin A. Serum CEA and NSE levels were high, 809.4 ng/ml and 85.8 ng/ml, respectively. After chemotherapy with modified FOLFOX6 for 2 months, the Paget lesion disappeared, and the primary anal canal tumor and liver metastases shrunk remarkably. Serum CEA and NSE levels decreased promptly to within normal ranges.

Conclusions: This is a clinically significant case, as it reveals novel pathological features about anal canal cancer with secondary Paget disease and successfully treated with modified FOLFOX6. Careful pathological investigation and appropriate treatment choice are needed for this rare cancer.

Keywords: Adenocarcinoma with neuroendocrine features; Anal canal cancer; Extramammary Paget’s disease; mFOLFOX6.

Fig. 1

CT scan showed diffuse liver metastases before treatment (a); cystic morphologically changed after 4 courses of mFOLFOX6 (b)

Fig. 2

Pathological examination of extramammary Paget disease (a, b, c, d) and primary lesion of anal canal (e, f, g, h) revealed poorly differentiated adenocarcinoma with neuroendocrine features. (HE: hematoxylin eosin staining, CK7/CK20: Cytokeratin7/20, GCDFP-15: gross cystic disease fluid protein-15)

Fig. 3

Paget disease was seen in perianal region before treatment (a) and disappeared after 4 courses of mFOLFOX6 (b)

Fig. 4

Endoscopy revealed the primary anal canal lesion like a submucosal tumor (a and b), which shrunk after 4 course of mFOLFOX6 (c and d)

Fig. 5

Patient’s clinical course. Remarkable tumor shrinkage and normalization of serum CEA and NSE levels continue for more than 11 months. (CEA, serum carcinoembryonic antigen; NSE, serum neuron specific enolase)