Introduction
Cancers of the appendix with coexistent tuberculosis is rare and most of them are found accidentally on surgical appendicectomy specimens performed for appendicitis.1 Both tuberculosis and malignancy are a global health problem and a cause of sufferings worldwide.2 The possible mechanism for the development of malignancy could be the break in the mucosal barriers with bacterial infection and the impaired cell mediated immunity. 3
Gastrointestinal tuberculosis most commonly involves the ileocecal region and tuberculosis of the appendix is rare. 3 The common appendiceal tumors are carcinoid, adenoma and lymphoma.2 Adenocarcinoma of the appendix accounts for only 0.08% of all appendiceal malignancies.2 It usually presents as appendicitis with evident lump or abscess. 4 The symptoms of weight loss, constipation, occult blood in stool and radiologic image of an appendicular and extensive ileocecal mass may be seen both in tuberculosis and cancer.5, 6 An endoscopic biopsy of the mass lesion is important to rule out a coexisting carcinoma.6
Case Summary
A 42-year-old lady presented to the surgery clinics with complaints of pain in the right iliac fossa with lump and fever for 4 months. There was no associated history of nausea, vomiting and altered bowel habits. On local examination, an ill defined firm swelling was felt over the right iliac fossa. No other lump or abnormality was detected.
Routine hematological investigations showed an increased total leucocyte count of 45,700/cumm with neutrophilia with raised ESR of 120 mm in first hour. USG abdomen revealed an ill-defined mass involving the appendix, extending to the ileo-caecal junction. Contrast enhanced computed tomography (CECT) of abdomen and pelvis showed an heterogenous mass lesion in the appendix with irregular thickened colo-caecal epithelial wall. Serum CEA levels were normal. A provisional clinical diagnosis of appendicitis with a colonic malignancy was given. On exploratory laparotomy, as the appendix was enlarged and inflamed with diffuse irregular thickening of the wall of the caecum and ascending colon, appendisectomy with right hemicolectomy was performed.
Grossly the appendix showed a 4 × 3 × 2.5 cm firm, grey-yellow solid growth at the tip with involvement of the adjacent caecum and ascending colon (Figure 1). Microscopic examination of the excised mass showed well-formed epithelioid granulomas comprising of epithelioid cells, langhan’s giant cells, lymphocytes and plasma cell with foci of caseous necrosis (Figure 2) admixed with areas of atypical gands with intracytoplasmic mucin, with marked cytologic atypia and necrosis (Figure 3). A diagnosis of tuberculosis with low-grade mucinous adenocarcinoma was given. All the sampled lymph nodes were negative for metastasis. The patient was administered adjuvant 6 cycles of 5-fluorouracil based chemotherapy. Currently, she is doing well, after 6 months of follow up period with no evidence of residual disease.
Figure 1
Grossly the appendix was enlarged with a 4 × 3 × 2.5 cm firm, grey-yellow solid growth at the tip with diffusely thickened adjacent caecum and ascending colon.
Discussion
The possible etiopathogenesis of coexistent carcinoma and tuberculosis may be the development of cancer with a previous history of chronic granulomatous infection and immunosuppression caused by cancer leading to increased tubercular susceptibility.5 Studies have reported that T-cell immunosuppression is associated with mycobacterial infections and may predispose to leukemias, lymphomas and carcinomas and visa versa.5, 6
Tanaka et al have reviewed 27 cases of coexistent tuberculosis and colon cancer, with a likely hypothesis that carcinoma predisposes to tubercular infection. 5 Jain et al have postulated that tubercular ulcer may be a risk factor of carcinoma, due to chronic inflammatory process and subsequent regeneration. 6 The toxic metabolites produced by the bacteria mixed with sterols in the bile play a role in the causation of colorectal carcinoma. 4 Also decreased natural killer (NK) cell activity, with increased chromosomal aberrations have been reported in coexistent carcinoma and tuberculosis. 5, 6
Carcinoma of the appendix is an incidental finding and accounts for less than 1.0% cases. 1 Carcinoids, adenocarcinomas, cystadenomas and lymphomas comprise the few appendiceal tumors. 3, 7 Adenocarcinoma is the most common histological type and presents clinically as acute appendicitis.7 Ileocaecum is the most common site for gastrointestinal tuberculosis.8 Chronic tubercular infection of the appendix is very rare and coexistent carcinoma is even rarer.
Clinical features of anorexia, weight loss, constipation, occult blood in stool and an extensive ileocaecal and ascending colonic mass may be seen in both tuberculosis and carcinoma. 5, 6 So a careful endoscopic biopsy of the colonic lesion is essential to rule out a coexisting carcinoma.9 A barium enema of such lesions may be predictive of overt malignancy of colon with an unduly long tailing segment, particularly in the proximal colon.
The treatment of appendiceal lesions is still debatable. Simple appendectomy is curable in appendiceal mucocele, and cystadenomas. 10 In a suspected case of malignancy of the caecum or the appendix, right hemicolectomy is the procedure of choice.10, 11 Appendisectomy with right hemicolectomy was performed in our case, as the appendix was enlarged and inflamed with diffuse irregular thickening of the wall of the caecum and ascending colon. Many oncologists recommend adjuvant 5-FU-based chemotherapy in patients with node-positive intestinal type adenocarcinoma. 11 The benefit of systemic chemotherapy for advanced disease is unknown and mucinous appendiceal adenocarcinomas are reported to be chemotherapy resistant. 11
Conclusions
The clinicians need to be aware of the protean manifestations of tuberculosis and carcinoma of the appendix and maintain a high index of suspicion in any appendicular lumpy lesion. Further research is required to determine, if a tuberculous infection may facilitate carcinogenesis and visa-versa.
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