Isolated appendicular tuberculosis.

Sir,

Tuberculosis of the appendix was described by Corbin as early as 1873.[1] It occurs as a primary or secondary disease, the former being rare with an incidence of 0.1%-0.6%.[23] Here, we report the case of a patient who presented with acute appendicitis who underwent appendectomy and the histopathology of the specimen revealed tuberculosis. She had no detectable tubercular focus elsewhere in the body. Preoperative diagnosis of isolated tuberculosis of appendix is rarely done. It needs high index of suspicion. It should always be confirmed by histopathology. Incidence, pathogenesis and various clinical presentations are also discussed briefly here.

Tuberculosis is one of the world's most widespread and fatal illnesses. In recent years, it has emerged as an important disease in both developing and developed countries, especially with the rising incidence of HIV infection. Abdomen is one of the common sites of extrapulmonary tuberculosis. However, appendicular involvement is found to be distinctly uncommon even in the set up of ileocaecal tuberculosis.[4]

Gastrointestinal tuberculosis is uncommon today because routine pasteurisation of milk has eliminated Mycobacterium bovis infections. Tuberculosis of the appendix presenting with the signs and symptoms of acute appendicitis is an even rarer entity. The pathogenesis of this isolated lesion is not clear. It may spread from neighbouring organs, from distant focus by haematogenous or lymphatic route or from lumen by infected intestinal contents when contaminated sputum is swallowed.[15] Appendix seems to be more frequently involved secondarily from ileocaecal tuberculosis.[6]

Here, we report a case of isolated appendicular tuberculosis, with no detectable focus elsewhere in the body. A 20-year-old woman presented with vomiting and acute onset of severe colicky abdominal pain in the right iliac fossa of one-day duration. On exploration, appendix was found inflamed. No pathology was observed in the ileum, caecum and mesentery. Appendicectomy was performed and specimen sent for histopathological examination. Microscopic appearance revealed tuberculous granulomas in the mucosa and submucosa of the appendix, which consisted of epithelioid cells, giant cells of Langhans type, lymphocytes, mononuclear cells and central area of caseous necrosis. Periappendicular tissue did not show any tuberculous lesion. The final diagnosis of tuberculous appendicitis was made [Figure 1].

Figure 1

Photomicrograph showing typical tubercles with epithelioid cells, lymphocytes, Langhans’ giant cells with central caseous necrosis

Tubercular appendicitis as the only manifest tuberculous lesion may present in three clinical forms.[7] The first type presents as an acute form that is indistinguishable from pyogenic appendicitis. The second clinical type is a chronic form presenting with vague pain, occasional history of vomiting, diarrhoea, and a mass in right iliac fossa. These cases are indistinguishable from cases of ileocaecal tuberculosis. The third type is latent and found accidentally on histopathological examination of the appendix. Our case appears to belong to the first clinical type.

The exact mechanism of involvement of the appendix remains unclear. The various ways by which the appendix can be involved include hematogenous, infected intestinal contents and extension of disease from neighbouring ileocaecal or genital tuberculosis.[7] Most of the literature regarding tuberculous appendicitis pertain to pre-chemotherapeutic era and the disease is seldom reported at present.[8] The rarity of primary tuberculosis of appendix may be due to the presence of minimal contact of appendicular mucosa with intestinal contents”.

It is not possible to make the correct clinical diagnosis because the clinical picture is that of acute appendicitis, without any signs suggestive of tuberculous infection of the organ. The diagnosis of appendicular tuberculosis is usually made based on histopathological examination of the appendectomy specimen, often received well after the patient has been discharged.[5] As tuberculosis is endemic in our country, it is strongly recommended that all surgically removed appendices should be sent for histopathological examination to exclude the suspicion of tuberculosis.[8]