Rectal adenocarcinoid with lymph node metastasis

Goblet cell adenocarcinoma of the anal canal with perianal Paget disease: A rare case report with literature review

INTRODUCTION

AS an uncommon neoplasm, goblet cell adenocarcinoma (GCA) is characterized by mixed endocrine-exocrine features. It is almost exclusively found in the appendix. Primary GCA of the anal canal is extremely rare.

CASE PRESENTATION

Herein we describe a novel rare case of 74-year-old Chinese female who is diagnosed with GCA in the anal canal with perianal Paget disease, including a brief review of the literature. In the lesion of anal canal, the tumor was composed of signet-ring-like cells on confluent growth model and copious mucin was produced as well. Simultaneously, the results of immunohistochemistry showed signet-ring-like cells were positive for CK20, CDX2, synaptophysin (Syn), CD56, carcinoembryonic antigen (CEA) and Villin. Meanwhile, the Ki67-labeling index reached 40%. In the lesion of perianal Paget disease, the small groups of atypical neoplastic cells were present in the epidermis. Immunohistochemically, the neoplastic cells were positive for CK20, CDX2 and epithelial membrane antigen, but negative for CK7, GCDFP15, S100, HMB45, and P63. The Ki67-labeling index reached 60% in the most concentrated spot.

CONCLUSIONS

Extra-appendiceal GCA was rare and easily under-recognizable. The diagnosis of GCA was seldom made preoperatively. Occasionally, GCA could occur in the anal canal accompanied by perianal Paget disease. So careful rectal examination was important in the patient with perianal Paget disease for avoid missing diagnosis of GCA on anal canal. GCA may show aggressive clinical behavior compared with typical well-differentiated neuroendocrine tumors. Therefore, we should pay more attention on the recognization of this rare disease.

Colorectal neuroendocrine carcinomas and adenocarcinomas share oncogenic pathways. A clinico-pathologic study of 12 cases

OBJECTIVE

Neuroendocrine carcinomas (NECs) are rare neoplasms with an increasing incidence. Oncogenetic pathways of colorectal NEC are still poorly understood, and no treatment standards are available for these rare tumors.

METHODS

We analyzed retrospectively the clinical records and histology of 12 patients with colorectal NEC. KRAS and BRAF mutations were investigated after the dissection of exoendocrine and neuroendocrine components. ALK alterations and EML4-ALK transcripts were detected by in-situ hybridization and determination of fusion transcripts, respectively.

RESULTS

At the time of diagnosis, the mean age of the patients was 60 years (40-79) and 10 patients had synchronous metastases. A transient response occurred in two patients and one patient treated with cisplatin-etoposide or fluoropyrimidine-oxaliplatin, respectively. Tumor progression-related death occurred in 11 of 12 patients. Ten tumors contained an exocrine component, accounting for 5-70% of the tumor, and the other two contained an amphicrine component. BRAF/KRAS mutations were found in six of 10 tumors, corresponding to BRAF(V600E) (n=2) or KRAS(G12D) (n=2), KRAS(G12V) or KRAS(G13D). DNA was obtained from both exocrine and endocrine components in seven cases, and the BRAF/KRAS status was identical in all cases. Split of the ALK locus was detected in a minority of tumor cells in two of eight cases, but EML4-ALK transcripts were absent.

CONCLUSION

The association of an exocrine component in all cases and the similar profile of BRAF/KRAS mutations indicate that colorectal NEC may correspond to a high-grade transformation of colorectal carcinoma. New chemotherapy regimens using targeted therapies should be assessed in these tumors.

A case of advanced rectal adenocarcinoid tumor with long-term survival

Adenocarcinoid tumor most commonly occurs in the appendix and a tumor arising in the rectum is extremely rare. A 58-year-old man underwent total pelvic exenteration with extended lateral lymph node dissection for rectal adenocarcinoid tumor invading the urethra with lateral lymph node metastasis. Microscopically and immunohistochemically, the tumor consisted of carcinoid-like components and signet-ring-cell-carcinoma-like components, and an adenocarcinoid tumor was diagnosed. Postoperatively, the patient received combination chemotherapy of fluorouracil and leucovorin as an adjuvant therapy. Three years and 5 years after the initial surgery, the patient developed left groin and left external iliac lymph node recurrences, and lymphadenectomy was performed each time. As a result, the patient is alive more than 5 years after the initial surgery. There is no consensus on the indication of surgical treatment for adenocarcinoid tumor. However, in advanced cases, an aggressive surgical procedure might result in long-term survival when resectable.