RECTAL CARCINOID

RECTAL CARCINOID: An Atypical Presentation

JAGDISH S NACHNANI, SAMEER A REGE, AMITA JOSHI*, OMPRAKASH ROHANDIA
Department of General Surgery and Pathology*, Seth GS Medical College and KEM Hospital, Parel, Mumbai 12.

Carcinoid tumours can involve all parts of gastrointestinal tract with a commonest presentation arising from the appendix, ileum and rarely rectum. Rectal carcinoid present as bleeding per rectum or are detected incidentally. We present a patient with rectal carcinoid who presented with a mass protruding per rectally along with chronic constipation.

INTRODUCTION

Carcinoid tumours are the most common endocrine tumours of the gastrointestinal tract. These can be either benign or malignant, based on the metastasis and invasion of the surrounding normal tissue. Carcinoids are classified as neuroendocrine or amine precursor uptake and decarboxylation tumours. Commonly the carcinoid tumours arise from the appendix, ileum and rectum. Rectal carcinoids present with bleeding per rectum or are incidentally detected. These carcinoids rarely metastasize and generally do not produce substances like serotonin and kallikrein.

CASE REPORT

A 45-year-old female patient presented to us with complaints of a mass protruding per rectum during defaecation since one month. The patient also had associated constipation since one month. There was no history of bleeding per rectum. There was no history of obstipation, vomiting or distension of abdomen. There was no history of flushing or diarrhoea or any chest complaints. She had no past history of any medical illness.

On examination, patient was stable with vitals maintained. The abdomen was soft with no lump palpable. There was no hepatomegaly. On per rectal examination, there was a firm, polypoidal growth around three centimeters in size palpable on the anterior rectal wall, four centimeters from the anal verge.

On investigations, the patient had haemoglobin of 10.6 gm. Plain radiograph of the chest and abdomen were normal. Ultrasonography of the abdomen showed multiple abdominal lymphadenopathy around the iliac vessels. Biopsy of the lesion was taken. The histopathology of the rectal biopsy specimen showed a carcinoid tumour beneath the mucosa composed of small uniform cells having an organoid pattern. The nuclei are uniform with open chromatin. The cytoplasm is abundant and no abnormal mitoses are seen (Fig. 1). The 24-hour urinary excretion of 5-hydroxy indole acetic acid level was within normal range. Computed tomography (CT scan) of the abdomen and colonoscopy did not reveal any synchronous lesion or metastasis. Patient was subjected to abdomino-perineal resection along with clearance of the lymph nodes. Patient is totally asymptomatic at 6 months follow-up.

DISCUSSION

Carcinoid tumour was first described by Langhans in 1867 with the classical symptomatology of carcinoid syndrome being described by Ransom in 1890.[1] These tumours arise from neuroendocrine cells of endodermal origin. The exact aetiology of these tumours is unknown.[2] Commonly these tumours arise from the appendix, ileum and rectum. The carcinoid syndrome occurs with bronchial or ovarian carcinoids or with gastrointestinal carcinoids that have metastasized to the liver. Carcinoid syndrome is a rare manifestation of rectal carcinoids and is present due to secretion of neuroendocrine hormones like serotonin and kallikrien. Only 1.6% of all neuroendocrine tumours produce carcinoid syndrome.[3] The main clinical features of this syndrome is flushing, diarrhoea, abdominal pain and bronchoconstriction.

Fig. 1: Photomicrograph of the histopathology slide showing carcinoid tumor beneath normal rectal crypts. (HE x 160).

The peak incidence of rectal carcinoids is in the sixth decade. There is no sexual preponderance and is not associated with intake of any food, race or geographical location.

Symptoms of the carcinoid depend on the site of origin. The most frequent presentation of rectal carcinoids is per rectal bleeding or they are found incidentally on rectal examination or lower endoscopy examination.[4] In our patient, the chief complaint was a mass protruding per rectally with a history of constipation. Rectal carcinoids do not classically produce carcinoid syndrome. Biochemically, rectal carcinoids do not produce serotonin. Carcinoid syndrome in these tumours is attributed to the secretion of somatostatin, neurotensin, pancreatic polypeptide and dopamine.[5]

The management of these patients depends largely on the size and anatomical location. Colonoscopy and CT scan are indicated to look for synchronous malignancies as well as presence of metastasis. If the size of the lesion is greater than two centimeters, as it was in our case, an abdomino-perineal excision is indicated if it is close to the anal verge.[6] Lesions higher up may be treated by an anterior resection. Also extensive surgery is indicated in cases of atypical histology. Local excision that is transanal or endoscopic is reserved for tumours less than one centimeter in size.[6]

The management of carcinoid syndrome includes hepatic artery embolisation for metastasis present in the liver or 5-fluorouracil infusion through the hepatic artery. Octreotide, a somatostatin analogue is used for amelioration of symptoms of carcinoid syndrome as well as in a case of carcinoid crisis.

Our patient presented with mass protruding per rectum on straining, with no other symptoms. All other investigations were normal. However, only histopathology could confirm the diagnosis.

ACKNOWLEDGEMENT

We are thankful to the Dean, Dr. Kshirsagar for allowing us to publish the hospital data.

REFERENCES

1. Ransom WB. A case of primary carcinoma of the ileum. Lancet 1890; 2 : 1020-23.

2.Cotran RS, Kumar V, Robbins SL. Robbins Pathologic Basis of Disease. The Gastrointestinal Tract. 5th ed. Philadelphia, WB Saunders. 1994; 818-20.

3.Saclarides TJ, Szeluga D, Staren ED. Neuroendocrine Cancers of the Colon and Rectum. Disease of the Colon and Rectum 1994; 37 : 635-42.

4.Orloff MJ. Carcinoid tumors of the rectum. Cancer 1971; 28 : 175-80.

5.Marshall JB, Bodnarchuk G. Carcinoid tumors of the gut: our experience over three decades and review of the literature. J Clin Gastroenterol 1993; 16 : 123-29.

6.Shirouzu K, Isomoto H, Kakegawa T, Morimatsu M. Treatment of rectal carcinoid tumors. Am J Surg 1990; 160 : 262-5.

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