JRSM >
Volume 94, Number 12 >
Pp. 643-644
Department of General Surgery, Oldchurch Hospital, Romford RM7 OBE,
UK
1
Department of Histopathology, Oldchurch Hospital, Romford RM7 OBE, UK
Correspondence to: Dr H Hashim, 38 King Henry's Reach, Manbre Road, London W6 9RH, UK E-mail: hash{at}cwcom.net
What seemed initially to be an appendiceal mass and subsequently a colon carcinoma proved to be a much rarer lesion.
CASE HISTORY
A woman of 69 was admitted with a two-day history of central colicky abdominal pain that localized to the right iliac fossa. Temperature was 38°C; there was a mass in the right iliac fossa with tenderness and guarding but no rebound tenderness. Her white cell count was raised at 18 x 109/L. The provisional diagnosis was appendiceal mass and she was treated with intravenous fluids and antibiotics (metronidazole and cefuroxime).
The symptoms settled and she was booked to have a barium enema as an outpatient. This showed a cauliflowerlike growth in the lateral border of the junction of the caecum and ascending colon (Figure 1) resembling a proliferative carcinoma. The patient was readmitted for an elective right hemicolectomy. At laparotomy an appendiceal mass was evident and the appendiceal wall seemed thickened with mesenteric stricturing. No tumour was identified on caecal colotomy, either in the caecum or in the ascending colon. The rest of the colon was unremarkable. The appendix was removed.
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On histological examination the appendix showed large numbers of macrophages containing periodic acid Schiff (PAS) positive diastase-resistant material within their foamy cytoplasm, admixed with lymphocytes, neutrophils, eosinophils and macrophages. Multinucleate giant cells were also noted. No organisms were seen on Gram-staining. The macrophages which were PAS diastase positive lay just beneath the luminal epithelial surface, lessening in number towards the submucosa. This appearance gave five differential diagnoses—the prodromal stage of measles, malakoplakia, Whipple's disease, histoplasmosis and Mycobacterium avium intracelullare infection.
In the prodromal stages of measles in children, Warthin—Finkeldey giant cells are usually seen; these were not present here. In malakoplakia, the macrophages contain Michaelis—Gutmann bodies which stain for calcium (Von Kossa) and for iron (Perl). Both these stains were negative. Infection by M. avium intracellulare was excluded by absence of staining for acid-fast bacilli (Ziehl—Neelsen). Histoplasmosis likewise was excluded by absence of staining for fungi (Groccot). Therefore Whipple's disease was diagnosed. On subsequent gastroduodenoscopy the oesophagus and duodenum appeared normal but there were multiple erosions in the gastric antrum. An antral biopsy specimen showed Helicobacter pylori-associated active acute and chronic gastritis. The duodenal (D2) specimen showed a normal villous architectural pattern without inflammation; Giardia lamblia was absent, and there were no histological features suggestive of Whipple's disease.
COMMENT
Whipple's disease is a rare multisystem disorder caused by Tropheryma whippelii, an actinobacterium; fewer than a thousand cases have been reported worldwide1. There seems to be a male preponderance, and Caucasians in the fourth and fifth decades of life seem particularly affected2. A genetic predisposition is suggested by the presence of HLA-B27 in 28-44% of patients compared with only 8% of the general population3. A search of the Medline database has revealed only one case report of Whipple's disease in the appendix4. That patient, too, had negative jejunal biopsies.
The usual presentation of Whipple's disease is with diarrhoea, weight loss, low-grade fever, lethargy, anaemia and hyperpigmentation. In addition to the intestinal tract it can affect lymph nodes, joints, eyes, heart valves, lung and the central nervous system.
Though the jejunum and ileum are commonly involved, Whipple's disease usually spares the duodenum. Small-bowel mucosa contains yellow-white plaques, the intestinal wall thickens and subepithelial yellowish lipid deposits are seen. Mucosal ulcers and petechial haemorrhages are sometimes reported. In advanced disease, the intestine appears thickened or dilated and rigid, with associated mesenteric thickening and lymphadenopathy. The oedematous mucosa acquires a coarse granular appearance. Mesenteric and retroperitoneal nodes become grossly enlarged and pale. Yellowish peritoneal plaques and massive infiltration of the mesenteric fat are characteristic. Histologically, the diagnosis depends on the demonstration of multiple rounded or sickle-shaped PAS diastase-resistant inclusions in the lamina propria macrophages (Figure 2). Some bacilli are seen within and between epithelial cells. PAS positive material is also seen in smooth muscle, endothelium and fibroblasts. The villi appear blunted and distorted by collections of foamy macrophages. These macrophages contain numerous secondary lysosomes which show rod-shaped bacteria on electron microscopy. The diagnosis can also be made by polymerase chain reaction (PCR) detection of the 16S ribosomal RNA5, although this test becomes negative earlier than microscopic changes and fresh tissue is required. Numerous attempts have been made to culture the bacteria but there is only one report of success—by use of human fibroblast cell lines from a heart valve inoculum6. Other experimental diagnostic techniques include use of interleukin-4-depleted macrophages7 and Hep 2 cells.
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Treatment is usually with long-term broad-spectrum antibiotics, but no controlled therapeutic studies have yet been done.
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