Primary linitis plastica of the rectosigmoid in a thirteen year old boy.

S Prasad, T Patankar, TT Zakaria, Z Patankar 
 Department of Radiology, Seth G. S. Medical College, Mumbai, India. , India

Correspondence Address:
S Prasad
Department of Radiology, Seth G. S. Medical College, Mumbai, India.
India

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::   Introduction

Primary scirrhous adenocarcinoma is the least common histologic subtype of primary gastrointestinal adenocarcinomas[1],[2]. This tumour exhibits a characteristic histologic pattern and distinct clinicobiologic behaviour, which have important diagnostic and therapeutic implications. The importance of early recognition and timely surgical intervention needs to be emphasised as the overall prognosis of this condition is poor.

::   Case report

A 13-year-old boy presented with peri-umbilical colicky pain for two days. He had constipation and rectal bleeding for one month. There was no family history of similar complaints. Per rectal examination revealed a hard, circumferential mass with near total obliteration of rectal lumen, four cm from the anal verge. The sigmoidoscope tube could not be negotiated through this narrowing. Laboratory investigations were normal. The plain abdominal radiograph showed multiple air fluid levels suggestive of mechanical large bowel obstruction. Contrast enhanced computerized tomographic (CT) scan [Figure:1] revealed " whorl  like" circumferential rectal wall thickening with marked luminal narrowing. Large bowel loops proximal to the rectum were dilated. The adjacent organs were normal. There was no evidence of lymphadenopathy or hepatic / peritoneal metastasis. Histopathological examination of the rectal biopsy specimen showed mucin secreting signet ring cells [Figure:2], diffusely infiltrating into the submucosa and muscularis propria. There was marked desmoplastic reaction in the submucosa. The patient underwent radical surgical resection of the tumour followed by a permanent colostomy from which he made an uneventful recovery. The patient was lost to further followup.

::   Discussion

The mucogenic, diffusely infiltrating and poorly differentiated variety of adenocarcinoma constitutes the scirrhous adenocarcinoma. Diffuse infiltrating carcinomas are rare and account for less than 1% of the total colorectal cancers. They are of two types, linitis plastica and lymphangiosis. Majority of scirrhous adenocarcinomas cause linitis plastica. Linitis plastica (Greek: linen cloth or net) coined by Brinton refers to the markedly rigid or contracted state of the organ afflicted by the neoplastic process. Laulman and Saphir[3] were the first to report primary linitis plastica type of carcinoma of the colon in 1951.

99 % of linitis plastica occurs in the stomach while the rest occur in the breast, gall bladder, pancreas, urinary bladder and colon[4]. Colorectal linitis plastica is extremely uncommon constituting less than 2% of carcinomas[1]. 78% of primary colorectal linitis plastica occur in the rectosigmoid segment. The rest of the left colon and the right colon accounts for 6% and 14% of the tumours respectively. In contradistinction, a majority of secondary colorectal linitis plastica (primary from the stomach) occur in the transverse colon owing to tumour spread through the gastrocolic ligament. Other tumours causing secondary linitis plastica include adenocarcinoma of the breast, gall bladder and prostate[1].

Patients usually present with nonspecific abdominal pain and alteration in bowel habits. Bowel obstruction or rectal bleeding is relatively uncommon. 20%30% of the tumours occur in patients with pre-existing ulcerative colitis[1]. Submucosal location of the tumour exhibiting centripetal growth pattern and late mucosal involvement leads to marked delay in onset of objective symptoms and detection by radiologicendoscopic examinations[1],[2].

On account of its stromal proliferation, the tumour exhibits marked predilection for mesenteric / peritoneal dissemination and spread to adjacent organs (notably ovaries in females)[1]. In contrast to primary adenocarcinoma, this tumour has fewer propensities for hepatic metastasis. The tumour is markedly stubborn due to frequent local recurrence/ peritoneal dissemination owing to centripetal tumour growth / peritoneal dissemination. The prognosis is uniformly poor with median postoperative survival period of one year due to rapid tumour growth and subsequent early / extensive metastases[5].

Colorectal carcinomas are relatively rare in children with clinical presentation similar to adults. There is no definite sex predilection. Children usually tend to present with advanced disease. Rao et al[6] reported a high incidence of advanced stage of colorectal cancer in children with 67% and 23% of children presenting with tumours in Dukes stage D and C respectively.

Barium studies and CT scan play a pivotal role in early diagnosis of scirrhous adenocarcinomas. Endoscopy has some limitations in the diagnosis of this condition[7]. Severe luminal narrowing may preclude endoscopic examination as was the case in our patient. The tumour may be difficult to recognise since the overlying mucosa is unaffected till late in the course of the disease. Significant falsenegative endoscopic biopsies and brushings result if carried in the absence of radiologic studies[7].

Typical imaging features include focal / circumferential wall thickening leading to luminal narrowing[2]. Long segment involvement is common with lesions more than 10 cms not uncommonly found. The presence of significant luminal narrowing (to less than 10 mm) is helpful in the initial CT detection of a scirrhous lesion[2]. Intramural calcification may be observed uncommonly. Contrast enhancement may be homogeneous or of the target pattern (due to relative mucosal sparing with marked oedema of the muscularis propria).

The list of differential diagnoses includes: lymphoma, scirrhous metastases, Crohn’s disease, ischaemic colitis, intramural haemorrhage and endometriosis[2]. Significant luminal narrowing, lack of bowel distensibility and features of colonic obstruction are suggestive of malignant process[2]. The target (double halo) configuration though usually found in inflammatory and ischaemic bowel disease is relatively specific for scirrhous carcinoma[2].

In conclusions colorectal cancer should be considered in the differential diagnoses in a child presenting with unexplained rectal bleeding, altered bowel habits, abdominal pain. Malignancy should not be excluded only on the basis of age. Timely radiologic and endoscopic examinations should be carried out to detect the tumour at an early stage and facilitate management.

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