September 15, 2007
Symptoms of Acute Appendicitis Caused By Primary Neuroma of the Appendix
By Rhoades, Torre Lohr, Joann; Jennings, Mark
ALTHOUGH THERE ARE SEVERAL benign appendiceal tumors, there is no clinical significance of benign tumors except when they cause obstruction of the appendiceal lumen and lead to acute appendicitis.1 We report a patient presenting with symptoms of acute appendicitis perhaps caused by an appendiceal neuroma. Case ReportA 43-year-old woman presented with a four-day history of right lower quadrant abdominal pain, generalized malaise, and anorexia. Her last menstrual period was one week before presentation.
Physical exam showed localized peritoneal irritation in the right lower quadrant. She was afebrile and other positive findings were absent. Laboratory studies were normal and a presumptive diagnosis of a viral illness was made. Abdominal ultrasound and computerized tomographic scan were normal. Laparoscopy was performed for persistent symptoms, and thorough inspection of suspected etiologies disclosed no abnormalities. Although there was no apparent evidence of pathology of the appendix, it was removed. The appendix measured 3.5 cm in length and 0.4 cm in diameter. When the appendix was sectioned, it was noted to have a very narrow lumen grossly. There were no inflammatory changes found on the microscopic report. The microscopic description showed fibrous obliteration of the appendiceal lumen. There were spindle cells noted to be within a myxoid background. Nerve fibers and ganglion cells were also noted. These findings were consistent with a diagnosis of appendiceal neuroma. The patient's pain slowly decreased and she was discharged to home three days after the exploratory laporoscopy with removal of the appendix.
Based on the literature review of appendiceal neuroma, it seems that this finding is a rare histologie finding. There are three microscopic histologie patterns for neuroma. A central obliterative appendiceal neuroma has a fibromyxoid core with patchy chronic inflammation and lymphoid aggregates. This type of neuroma occurs most commonly. The lesion consists of loosely arranged aggregates of spindle cells in a background network of eosinophilic cell processes. The proliferation of the lumen consists of fibrous tissue that rests on the submucosa. There is an extensive capillary network throughout each appendiceal neuroma. The second type is described as an intramucosal pattern. These findings are similar to the neural proliferation of central obliterative appendiceal neuroma. The third type of neuroma is the nodular appendiceal neuroma.
The significance of a histologie diagnosis of appendiceal neuroma is thought to be an incidental finding in acute appendicitis. Appendiceal neuroma is potentially a precursor to carcinoid. Carcinoid tumors are characterized with neuron-specified enolase and by neurosecretory granules that are found on electron microscopy. These cells have been designated subepithelial neurosecretory cells (SNC) and have been suggested to be preprogenitors of appendiceal carcinoid tumors.2- 3 Both SNC and carcinoid show an affinity for argentaffin stains. The nest and rosettes formed by SNC are found in half of appendiceal carcinoids. There is variation in electron density of the core of the granules believed to be due to the different states of maturation and proliferation. These findings all suggest that SNC is a progenitor cell of carcinoid tumors. Patients and normal evaluation may, on occasion, have benign appendiceal processes such as fibromas and neuromas. This patient's pathology may have been a coincidental finding, not related to her symptoms. However, after her appendectomy, her symptoms resolved. This could represent an early presentation for appendiceal neuromas because the lumen of the appendix was narrowed and could have been contributing to her pain.
1. Chan W, Fu KH. Value of routine histopathological examination of appendices in Hong Kong. J Clin Path 1987;40:429-33.
2. DeLellis RA, Dayal Y, Wolfe HJ. Carcinoid tumors: Changing concepts and new perspectives. Am J Surg Path 1984;8:295-300.
3. Rode J, Dhillon AP, Papadaki L, Griffiths D. Neurosecretory cells of the lamina propia of the appendix and their possible relationship of carcinoids. Histopathology 1982;6:69-79.
TORRE RHOADES, M.D., JOANN LOHR, M.D., MARK JENNINGS, M.D.
From the Department of Surgery, Good Samaritan Hospital, Cincinnati, Ohio
Presented during Poster Grand Rounds at the Annual Scientific Meeting and Postgraduate Course Program, Southeastern Surgical Congress, Lake Buena Vista, FL, February 18-21, 2006.
Address correspondence and reprint requests to Torre Rhoades, M.D., c/o Joy Rusche, Hatten Research Institute-11J, Good Samaritan Hospital, 375 Dixmyth Avenue, Cincinnati, OH 45220. E-mail: [email protected]
Copyright Southeastern Surgical Congress Aug 2007
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