Rosai-Dorfman disease of the cauda equina: illustrative case.

BACKGROUND: Rosai-Dorfman disease (RDD) is a rare, nonmalignant histiocytosis. It typically occurs in lymph nodes, skin, and soft tissues, but numerous reports of central nervous system involvement exist in the literature. The peripheral nervous system has rarely been involved. In this study, the authors present a case of RDD isolated to the cauda equina. The presentation, management, surgical technique, and adjunctive treatment strategy are described. OBSERVATIONS: A 31-year-old female presented with 6 months of progressive left lower-extremity numbness involving the lateral aspect of the foot and weakness of the left toes. Magnetic resonance imaging of the lumbar spine demonstrated a homogeneously enhancing intradural lesion involving the cauda equina at the L2-3 levels. Histopathology after resection revealed a histiocytic infiltrate, positive for CD68 and S100, and emperipolesis consistent with RDD. No adjuvant therapy was administered, and the patient had full remission at the 1-year follow-up. Only five other cases of intradural RDD lesions of the cauda equina have been reported in the literature. LESSONS: RDD of the cauda equina is an especially rare and challenging diagnosis that can mimic other dura-based lesions, such as meningiomas. A definitive diagnosis of RDD relies on pathognomonic histopathological and immunohistochemical findings.

Signet-ring cell carcinoma in gastric biopsies: expecting the unexpected.

AIMS: This study was designed to establish the relative prevalence of intestinal-type and signet-ring carcinoma in gastric biopsy specimens from ambulatory patients, to determine the percentage of signet-ring carcinomas that could be expected based on the available clinical and endoscopic information, and to estimate the likelihood of missing a tumour. METHODS: We extracted data of all patients with a diagnosis of primary gastric carcinoma from a national pathology database. We then reviewed clinical information and original slides, classified tumours as intestinal or signet-ring-type, and categorised the latter as 'unexpected' (no alarming symptoms, no mention of suspicious lesions) or 'expected' (clinical or endoscopic information suggestive of tumour). Unexpected signet-ring carcinomas were categorised as 'obvious' or 'challenging' (rare signet-ring cells; immunohistochemical stains used to confirm the nature of the infiltrates). RESULTS: There were 310 109 patients with gastric biopsies; 615 patients had primary gastric carcinoma (359 intestinal and 256 signet-ring-type). Gastric cancer was more common in men (OR 2.54; 95% CI 2.05 to 3.14; p<.0001) for intestinal-type and (OR 1.90; 95% CI 1.48 to 2.42; p<0.0001) for signet-ring cell type). Intestinal-type carcinoma occurred in older patients than signet-ring-type (median age 74 vs 65 years, p<0.001). There were 196 expected and 60 unexpected signet-ring carcinomas; 47 of the 60 unexpected cases were histopathologically obvious. Thus, only 13 signet-ring carcinomas (1 in 25 000 gastric biopsy sets) were truly unexpected. CONCLUSIONS: Signet-ring carcinoma is a rare finding in gastric biopsy specimens from ambulatory patients; routine due diligence and the clinical/endoscopic information provided are usually adequate to raise pathologists' index of suspicion.

Magnetization transfer helps detect intestinal fibrosis in an animal model of Crohn disease.

PURPOSE: To determine the utility of magnetization transfer (MT) in the identification and quantification of intestinal fibrosis in a rat model of Crohn disease. MATERIALS AND METHODS: The university committee on the use and care of animals approved this study (UCUCA 08592). Lewis rats injected subserosally with peptidoglycan-polysaccharide (PG-PS) develop bowel inflammation 1 day after laparotomy (early phase) and fibrosis starting 14 days after laparotomy (late phase). The authors performed 2.0-T magnetic resonance (MR) imaging in 25 rats injected with PG-PS and 13 injected with human serum albumin (HSA) (control animals). Imaging was performed before laparotomy and on a weekly basis thereafter for up to 28 days. The MT ratio in the bowel wall was calculated. Resected cecal tissue was scored for inflammation and fibrosis. Tissue fibrosis was determined with colorimetric analysis of trichrome-stained specimens. Collagen content was measured with Western blot analysis. Statistical analyses were performed with the Student t test for continuous bivariate comparisons, the Pearson correlation for continuous variables, and the Spearman correlation for ordinal variables. RESULTS: All rats developed early inflammation, which subsided over time. Rats injected with PG-PS developed increased fibrosis in the late phase, whereas control rats did not. The mean MT ratio of rats injected with PG-PS with late-phase fibrosis was higher than that in rats with early phase inflammation (P = .017). In addition, the MT ratio of rats injected with PG-PS with late-phase fibrosis was higher than that of control animals that did not develop fibrosis in the late phase (P = .0001). The MT ratio of control animals remained unchanged over time as inflammation subsided. The MT ratio in rats injected with PG-PS showed correlation with tissue fibrosis (ρ = 0.63). The MT ratio showed correlation with tissue collagen (R = 0.74). The positive and negative predictive values of the MT ratio in the prediction of fibrosis were 92% (12 of 13 rats) and 83% (five of six rats), respectively. CONCLUSION: These results indicate that MT is sensitive to bowel wall fibrosis as occurs in Crohn strictures.

Lymphocytic esophagitis: a chronic or recurring pattern of esophagitis resembling allergic contact dermatitis.

Lymphocytic esophagitis (LE) is characterized by intraepithelial lymphocytes (IELs) and spongiosis, resembling contact dermatitis. LE has been defined as high numbers of IELs and no or rare granulocytes and was found in young patients and in association with Crohn disease (CD). We reviewed the medical records of 42 LE cases. Cases were divided into severe (IELs in interpapillary and peripapillary fields) and mild (IELs in peripapillary fields) LE. The control group included specimens from 34 consecutive esophageal biopsy cases. Mean ages were similar (LE, 44 years; control subjects, 43 years). CD was present in 5 LE cases (12%) and 1 control case, an insignificant difference. Of patients with LE, 14 (33%) had an allergy; 11 (26%), gastroesophageal reflux disease (GERD); 4 (10%), Helicobacter pylori gastritis; and 18 (43%), dysphagia. No differences were found in clinical features between LE and control cases, except GERD was less common in severe LE (6/30 [20%]) than in control cases (17 [50%]). No patient with LE had celiac disease. No medications were common among LE cases. Patients with LE are statistically no more likely than control subjects to have CD. We found no association between LE and any clinical condition or symptom. Based on sequential biopsies in 7 patients, LE seems to be a chronic disease.