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Mucocele of the appendix is rare and occasionally is accompanied by calcification. In a recent case, an eggshell-thin calcified mucocele fractured to produce an acute abdomen. This situation was not found in a review of the literature. A brief summary of the properties of mucocele is presented.
During an operation for suspected appendicitis, the surgeon concluded that the appendix was absent. The causes of this situation are presented and a guide to its management is suggested.
Examination of 182 appendices containing Enterobius vermicularis demonstrated that male pinworms are seen more commonly than female. There was no association between the sex of pinworms and inflammation in the appendix but inflammation was frequently seen in association with luminal ova. Ova release from female pinworms may be a feature of appendiceal obstruction.
The clinicopathological features of schistosomiasis of the appendix are discussed, based on the clinical presentation, operative findings and morphological changes in the specimens of patients seen in Ibadan between 1980 and 1989. Schistosoma haematobium was implicated as the causal agent of a granulomatous inflammatory reaction with eosinophilia and fibrosis. Intramuscular oviposition was associated with frank acute appendicitis, and serosal involvement resulted in peritoneal adhesions, with ileoileal intussusception in one patient. The actual role of schistosomal infestation as a contributory factor in appendicitis is still open to debate, but the diagnosis must be entertained in patients in the tropics with features of acute appendicitis or recurrent abdominal pain.
Standard roentgenographic criteria for anterior-posterior (AP) displacement of the kidney may not reveal small, uniformly distributed, perirenal masses. Ultrasound, on the other hand, is an axial display and thus is quite sensitive to such changes. A case of ruptured retrocecal appendix is presented in which the intravenous pyelogram was negative. In the sonogram, however, a slight separation was seen between the renal parenchyma and the posterior abdominal muscle wall. This led to further investigation and the diagnosis of an unsuspected retrorenal abscess.
The apico-basal distribution of lymphocytes within the epithelium covering the domes of lymphatic tissue in the wall of the rabbit appendix was investigated in single and serial sections stained either for general histology, for cytoplasmic basophilia and acidophilia, or for nonspecific esterase activity. From the base to the summit of a dome, four zones numbered proximo-distally 1-4 were distinguished. Epithelial cells migrate from base to summit, as indicated by mitotic figures in zone 1, the gradual change from cytoplasmic basophilia to acidophilia in zones 2 to 4, and visible extrusion of cells from zone 4 at the summit. Zone 1 was free of lymphocytes. Most of the lymphocytes in zone 2 were intercellular and randomly arranged, but a few in this zone were within tapered epithelial cells modified by a process extending basally to the basement membrane. Small numbers of these tapered epithelial cells also occurred in zone 3. The large clusters of ten to 12 lymphocytes that characterized zone 3 were intercellular and impinged the apical regions of epithelial cells. Serial sections at the level of the distal cluster of zone 3 showed lymphocytes located also more basally, and some of these lymphocytes appeared to be passing through the basement membrane back into the lymphoid tissue of the dome. Epithelium of zone 4 over the distal surface of a dome was largely free of lymphocytes. Apparently most infiltrating lymphocytes form intercellular clusters and then return to the subepithelial lymphatic tissue.
Extraepithelial, extraglandular endocrine cells of types EC1 and EC2 occur in the lamina propria of the normal appendix. They are more numerous in intramucosal neurogenic appendicopathy. Ultrastructurally there is invariably a close association between the cells and non-myelinated nerve fibres of the mucous plexus. Together they form a complex surrounded by a common basal lamina, and the term enterochromaffin cell-nerve fibre complex (ECC-NF) is suggested for this morphological and functional unit. The derivation of extraepithelial EC cells from the glandular epithelial cells could not be established and the existence of the complexes is held to support an origin from neuroendocrine-programmed ectoblasts.
In order to clarify the histogenesis of appendiceal carcinoid tumours, epithelial (ENC) and subepithelial (SNC) neuroendocrine cells were counted at four sites in 50 normal appendices stained by standard argyrophil and argentaffin techniques. In general, ENC were present in similar number at all sites within the appendix, whereas SNC were more numerous at the tip than at the base. The number of ENC was similar throughout life, apart from an increase in one neonate and some elderly patients, whereas SNC were maximal in young adults. Thus, the topographical and age distributions of SNC, but not those of ENC, parallels the topographical and age incidence of appendiceal carcinoid tumours, suggesting that most appendiceal carcinoid tumours arise from SNC rather than ENC.
In order to develop protective antibodies against a wide range of potentially infectious pathogens, the young rabbit must diversify a limited initial repertoire by somatic mechanisms (the high copy number primary repertoire). The majority of rabbit B cells produce heavy chain variable regions by rearranging the VHa allotype-encoding VH1 gene. Thus in normal rabbits the majority of serum immunoglobulins bear VHa allotype (due to VH1 FR1 and FR3 sequences). The young rabbit appendix is a site of diversification of rearranged VH genes by gene-conversion-like and somatic hypermutation mechanisms. The newly generated B cells probably undergo selection processes that involve foreign and self-antigens and superantigens. We find preferential expansion and survival of B cells in normal and VH-mutant ali/ali rabbits based on their heavy chain FR1 and FR3 sequences (VHa allotype). This selection may involve "superantigen"-like interactions with endogenous as well as exogenous ligands.
The distribution of intestinal membranous (M) cells has been studied within the follicle-associated epithelium of rabbit Peyer's patches and appendix. Vimentin expression has been assessed as a primary criterion to identify rabbit M cells in tissue sections and in whole tissue preparations. This criterion has been compared to the use of the absence of alkaline phosphatase which, due to its heterogeneous distribution within the enterocyte population, is less reliable than vimentin expression as a marker for rabbit M cells. The pattern of vimentin immunostaining revealed that the majority of M cells are located in the periphery of the follicle-associated epithelium, the dome apex being largely free of M cells. This distribution was confirmed by scanning electron microscopy. Vimentin is also expressed by follicle-associated epithelial cells in the vicinity of crypts which lack the typical lymphocyte-containing pocket of M cells. Cytoplasmic peanut agglutinin binding coincides with vimentin-expression throughout the follicle-associated epithelium but is absent from vimentin-negative enterocytes. The co-localisation of these two phenotypic markers in both M cells and epithelial cells adjacent to crypts, which lack the typical morphology of fully developed rabbit M cells, suggests that they correspond to immature M cells which by their location appear to derive directly from undifferentiated crypt stem cells and not from mature columnar enterocytes.
Thirty-one children underwent appendectomy following administration of a single i.v. dose of clindamycin 10 mg/kg or metronidazole 7.5 mg/kg. The serum levels of the antibiotics at that time were comparable, but the tissue concentration of clindamycin in the appendix (mean 7.23 micrograms/g) exceeded that of metronidazole (mean 2.27 micrograms/g). The concurrent mean concentration of metronidazole in peritoneal fluid (14.26 micrograms/ml) was higher than that of clindamycin (7.72 micrograms/ml).
A case of Crohn's disease limited to the appendix is reported. A preoperative ultrasonic study of the lower right abdomen revealed an interesting appearance that we named the "milky way sign." Microscopic findings in the resected specimen confirmed that the sign represented adipose tissue of the mesoappendix that had become involved by transmural inflammation. This seems to be highly suggestive of Crohn's disease.
A patient with massive gastrointestinal hemorrhage found to be bleeding from a diverticulum of the appendix is presented. Appendectomy was curative and pathologic changes were those associated with colonic diverticular hemorrhage. A review of the literature reveals this to be a previously unreported cause of gastrointestinal bleeding.
The isolation of viable lymphocytes from fresh human appendices is described. Under standardized experimental conditions of cell preparation no selective enrichment of either T- or B-lymphocytes was observed. The mean percentage of T-lymphocytes as judged by spontaneous rosette formation found in 34 appendices examined was 50.0%. After overnight incubation surface-Ig was detected by immunoradioautography on 46.8% of the recovered lymphocytes from 10 appendices. For the detection of surface-Ig specifically purified antibodies to heavy chains mu, gamma and alpha were used. Of the 46.8% surface-Ig positive lymphocytes the class distribution was as follows: IgM 17.7%, IgG 24.4% and IgA 4.7%. The isolated lymphocytes showed a variable mitotic response to PHA (stimulation index ranging from 3.3 to 200.9) as well as to allogeneic lymphocytes in a one-way mixed lymphocyte culture. So far, a distinct correlation could not be found between the histological degree of inflammation and the class or mitotic response of appendix lymphocytes.
A meniscus was produced in a gas-filled appendix by the outline of the obstructing appendicolith. This meniscus appearance should be specific for appendicitis since it represents the obstructing stone. This sign can be elicited by oblique or other projections, perhaps with fluoroscopic control.
A case of calcified and infected mucocele of the appendix is reported. The appearance of the calcification, the presence of gas with an air fluid level on plain films, and the opacification of the lumen of the mucocele by opaque enema allowed the correct radiologic diagnosis to be made.
Vermiform appendix is an unusual site of diverticulosis. We present 3 examples of this entity and briefly review its pathogenesis and clinical significance. As a general rule, appendiceal diverticula are multiple, acquired naturally, and rarely associated with complications.
The existence of chronic appendicitis is controversial. In this prospective study, we investigated possible changes in the innervation of the appendix under different pathological conditions and correlated histological findings with clinical observation. Thirty appendectomy specimens and 14 appendices obtained from organ donors or patients who underwent right hemicolectomy were immediately fixed in Bouin's solution and processed for immunocytochemistry using an antiserum directed against the panneuronal marker protein gene product 9.5 (PGP 9.5). The density of PGP 9.5 immunostaining was evaluated by digitized morphometry. Significant differences in the density of the PGP 9.5-immunoreactive area were detected in the mucosal layer. In the nonacute appendicitis group, PGP 9.5 was increased (10.99 +/- 3.15%) as compared to acute appendicitis (3.89 +/- 1.77%) and controls (4.98 +/- 1.25%). The significant increase of PGP 9.5 in nonacute appendicitis may suggest axonal sprouting leading to hyperinnervation of the mucosa. This may be a neuronal factor in the pathophysiology of the disease and pain symptoms.