Margie A. Scott

Immunohistochemical Characterization of Benign Laryngeal Lesions

It has been proposed that laryngeal nodules and polyps represent injury to the basement membrane zone of the vocal fold. Repeated trauma from shearing forces produced by excessive or abusive phonation leads to basement membrane zone disruption and thickening. This thickening, along with poorly understood vascular changes, creates the characteristic clinical appearance of the vocal nodule or polyp. As such, to better understand vocal fold nodules it is imperative to characterize the extracellular matrix in this area of injury. Secondary to the small size and relatively acellular nature of these lesions, hematoxylin and eosin (H & E) preparations of histologic material are unsatisfying. A previous study examined this area with immunohistochemical techniques to better characterize its contents. The report, however, contained little information with regard to the clinical appearance of the lesions prior to excision. Therefore, we were prompted to review histologic material from 31 patients who underwent microsurgical excision of 41 benign lesions, vocal nodules (4), polyps (19), polypoid corditis (4), and cysts (14) with immunohistochemical techniques to characterize the patterns of fibronectin and collagen type IV within these lesions. Normal human vocal folds were stained for control. All material was correlated with the H & E preparations and the clinical diagnosis. Collagen type IV and fibronectin appeared present in relatively abnormal patterns in the areas adjacent to the lesion. This study validates earlier results. In addition, correlation with clinical data allows association of immunohistochemical staining patterns with clinical diagnosis.

Pathogenic Yersinia DNA is detected in bowel and mesenteric lymph nodes from patients with Crohn's disease

Previously, we detected pathogenic (invasive) Yersinia DNA in the appendices of two patients who later developed Crohns disease (CD). This subsequent investigation is the first to evaluate a series of specimens from CD patients for the presence of pathogenic Yersinia DNA. A total of 54 intestinal resection specimens from 52 patients with confirmed CD were evaluated. Lesional tissue was tested by polymerase chain reaction analysis for the presence of genes occurring only in pathogenic Yersinia. Primer pairs are specific for each species, with no known cross reactions with other bacteria. Forty normal bowel specimens, 30 cases of acute appendicitis, and 50 cases of various active colitides served as disease controls. Medical records were reviewed following polymerase chain reaction and histologic evaluation. A total of 17 of 54 resections (31%) contained Yersinia DNA by polymerase chain reaction. Mesenteric lymph nodes were also positive in eight of these cases. All controls were negative. Yersinia-positive patients had carried the diagnosis of CD for a median of 10 years before resection (range 1 month to 40 years). We report the first documentation of Yersinia DNA in a series of CD cases. Further studies are needed, including serial study, over time, of Yersinia-positive CD patients, as well as prospective studies of newly diagnosed CD patients for evidence of Yersinia infection. Like previous studies associating infectious organisms with CD, much work remains to elucidate whether the presence of Yersinia DNA is an epiphenomenon or actually a factor in the pathogenesis of CD.

The pathologic spectrum of gastrointestinal and hepatic histoplasmosis

We characterized the pathologic spectrum of lesions in gastrointestinal and hepatic histoplasmosis by studying cases of disseminated disease in immunocompromised and immunocompetent patients from endemic and nonendemic areas. We evaluated 56 specimens from 52 patients with H&E and silver stains. Of these patients, 43% presented with gastrointestinal rather than pulmonary symptoms. Thirty-one percent had gastrointestinal lesions, 10% had liver lesions, and 43% had both. Gross gastrointestinal features included ulcers (49% of patients), nodules (21%), hemorrhage (13%), obstructive masses (6%) and normal mucosa (23%). Microscopic gastrointestinal findings included diffuse lymphohistiocytic infiltration (83%), ulceration (45%), lymphohistiocytic nodules (25%), or minimal inflammatory reaction (15%) but only rare well-formed granulomas (8.5%). The most common hepatic finding was portal lymphohistiocytic inflammation; discrete hepatic granulomas were seen in less than 20% of involved livers. The pathologist must be aware of the broad range of gastrointestinal and hepatic lesions produced by histoplasmosis and, in particular, that well-formed granulomas are rare. Given the appropriate clinical context, histoplasmosis should be considered in both immunocompetent and immunocompromised patients, regardless of pulmonary symptoms, in nonendemic as well as endemic areas.

The role of Yersinia enterocolitica and Yersinia pseudotuberculosis in granulomatous appendicitis: A histologic and molecular study

Granulomatous appendicitis is an enigmatic entity. Purported causes include Crohns disease, foreign body reactions, sarcoidosis, and infectious agents; however, most cases remain idiopathic. Yersinia enterocolitica (YE) and Y. pseudotuberculosis (YP) have been implicated as causes of appendicitis, ileocolitis, and mesenteric adenitis. The authors examined the potential role of YE and YP in granulomatous appendicitis using histologic and molecular methods. Forty cases of granulomatous appendicitis were evaluated for histologic features including transmural inflammation, number and character of granulomas, and mucosal changes. Twort Gram, Grocott methenamine-silver (GMS), and Ziehl–Neelsen stains were evaluated, and polymerase chain reaction (PCR) analysis was performed to identify pathogenic YP and YE. Twenty-five percent (10 of 40) of the cases were positive for pathogenic Yersinia by PCR (four YE, four YP, and two with both species). Prominent histologic features included epithelioid granulomas with lymphoid cuffing, transmural inflammation with lymphoid aggregates, mucosal ulceration, and cryptitis. One Yersinia-positive case contained mural Gram-negative bacilli; fungal and acid-fast bacilli stains were all negative. Except for one culture-negative case, serologies and cultures were not done or results were unavailable. Two Yersinia-positive patients were diagnosed subsequently with Crohns disease, suggesting a possible relationship between the two entities. No other patients developed significant sequelae. YE and YP are important causes of granulomatous appendicitis, and Yersinia infection may mimic Crohns disease. No histologic features distinguish reliably between Yersinia species, or between Yersinia-positive and Yersinia-negative cases. Because special stains and cultures are often not diagnostic, PCR analysis is an excellent technique for the diagnosis of Yersinia.

Cat-scratch disease: historic, clinical, and pathologic perspectives.

Cat-scratch disease (CSD) initially was described in 1931, but the etiologic agent (Bartonella henselae) was not elucidated until decades later. This disease is the most common cause of chronic lymphadenopathy among children and adolescents, characteristically manifesting as subacute regional lymphadenitis with an associated inoculation site due to a cat scratch or bite, often accompanied by fever. The hallmark histologic lesion is granulomatous inflammation with a central stellate microabscess. Numerous atypical manifestations of CSD have been described, and these often lack the characteristic superficial lymphadenopathy and inoculation site papule. These atypical forms may be misdiagnosed initially as other infectious processes or neoplasms. We present a review of the history and epidemiologic features of CSD, describe common and unusual clinicopathologic manifestations, and discuss current diagnostic modalities.

Histologic and molecular diagnosis of tularemia: a potential bioterrorism agent endemic to North America.

Francisella tularensis (FT), a zoonotic bacterium that causes tularemia, has received attention as a possible bioterrorism threat. We developed a PCR assay for use in fixed, processed tissues, which are safer to handle and allow archival testing. PCR analysis for a 211-bp fragment of the FT lipoprotein gene was performed on tissues from 16 cases of tularemia. In all, 14/15 cases with intact DNA (93%) were positive for FT by PCR. Frequent histologic findings in PCR-positive tissues included irregular microabscesses and granulomas in liver, spleen, kidney, and lymph nodes, and necrotizing pneumonia. Unusual cases featuring suppurative leptomeningitis and gastrointestinal ulcers were also seen. As this disease is endemic in North America, and has been identified as a potential bioterroristic threat, awareness of the clinicopathologic spectrum of disease and available detection methods is increasingly important. This PCR assay, the first designed for use in processed tissues, is an excellent method for diagnosis of tularemia.

Value of Videostroboscopic Parameters in Differentiating True Vocal Fold Cysts From Polyps

Differentiating between benign true vocal fold (TVF) cysts, polyps, and nodules on the basis of their gross appearance would be advantageous in determining the need for surgical therapy. A retrospective study of 32 patients covering 31 months was done to assess the ability to differentiate these lesions on the basis of stroboscopic parameters. Stroboscopic examinations were evaluated for symmetry, amplitude, periodicity, mucosal wave, and closure. Preoperative diagnoses were validated with operative and histologic confirmation.

Fatal meningitis and encephalitis due to Bartonella henselae bacteria.

Bacterial infection due to Bartonella henselae commonly develops in children and young adults following cat/dog contacts and/or cat/dog scratches. Regional lymphadenopathy is its most common clinical expression. However, encephalitis and Parinauds syndrome (oculoglandular syndrome) have also been reported as has systemic illness. A review of the international literature in all languages revealed no fatal complications in immunocompetent hosts. A four-year-old white child with no underlying illness began to have seizure-like activity. She was taken to a local hospital and subsequently transferred to a medical center. The child was treated aggressively for seizures and fever of unknown origin. However, her condition rapidly declined and she died without a specific diagnosis. At autopsy there was marked cerebral edema with no gross evidence of acute meningitis. Microscopic exams revealed multiple granulomatous lesions as well as a meningitis and encephalitis. A variety of cultures and stains were negative for acid fast and fungal organisms. Warthin-Starry stains of involved tissue including brain and liver revealed pleomorphic rod shaped bacilli consistent with Barronella henselae. Analysis of brain tissue with polymerase chain reaction (PCR) and Southern blot for the deoxyribonucleic acid (DNA) was definitive for DNA of Bartonella henselae bacteria.

Molecular detection of Campylobacter jejuni in archival cases of acute appendicitis

The role of enteric bacteria in the pathogenesis of acute appendicitis is a controversial subject. Campylobacter jejuni has been previously demonstrated in a minority of cases of acute appendicitis using microbiological or immunohistochemical methods, notably in cases where inflammation was limited to the mucosa/submucosa. Our goal was to evaluate cases of acute appendicitis for C. jejuni DNA using molecular methods, and to compare our findings to the histologic features. In total, 50 archival cases of acute appendicitis were selected, and PCR was performed using primers targeting a 286-bp fragment of the mapA gene specific to C. jejuni. Twenty histologically unremarkable appendectomy specimens served as negative controls. Cases were reviewed with attention to particular histological features including mucosal ulceration, cryptitis, depth of inflammatory infiltrate, and the presence of mural necrosis. Of acute appendicitis cases, 22% (11/50) were positive for C. jejuni DNA by PCR analysis. Control cases were negative for C. jejuni DNA. All patients presented with signs and symptoms typical of acute appendicitis. Of the C. jejuni positive cases, only 27% contained acute inflammation limited to the mucosa/submucosa, whereas the remainder had mural or transmural inflammation; therefore, the histological features of C. jejuni-positive acute appendicitis cases were indistinguishable from C. jejuni-negative cases. In summary, C. jejuni DNA was detected in a significant percentage (22%) of acute appendicitis cases, a much higher percentage than previous studies using other methodologies. As C. jejuni is an enteric pathogen that does not exist as a commensal or nonpathogenic organism, the presence of C. jejuni DNA implies current or recent infection. Further study is needed to determine whether the presence of C. jejuni DNA in acute appendicitis indicates appendiceal involvement by C. jejuni enteritis, or if there is a true causative role for C. jejuni in acute appendicitis.

Molecular diagnosis of Campylobacter jejuni infection in cases of focal active colitis.

Campylobacter jejuni (CJ) is the most commonly isolated stool pathogen in the United States. Biopsy findings are typically those of focal active colitis (FAC), a nonspecific pattern usually indicating infection or adverse drug effect that is characterized by focal cryptitis and preservation of crypt architecture. We developed a molecular test for CJ that can be performed on routinely processed gastrointestinal biopsy specimens, and assessed what percentage of patients with biopsy findings of FAC have molecular evidence of CJ infection. One hundred and ten colon biopsies diagnosed as FAC were retrieved from three institutions. Polymerase chain reaction (PCR) was performed following DNA extraction; primers were designed to target a 286-bp fragment of the mapA gene that is specific to CJ. Pure genomic DNA derived from cultures served as the positive control; reagent blanks and 50 normal colon specimens served as negative controls. Nineteen percent (21/110) of the FAC biopsies were positive for CJ DNA by PCR analysis. Fourteen CJ-positive patients presented with diarrhea, 3 presented with gastrointestinal bleeding, and 3 had incidental FAC found on screening colonoscopy. Ten patients had abnormal colonoscopic findings, including erythema (4), ulcers (4), colitis (1), and hemorrhage (1). As CJ is an enteric pathogen that is not present in the gut as a commensal organism, the presence of CJ DNA suggests current or recent previous infection in these patients. CJ infection should be considered in patients with diarrhea and colon biopsies showing FAC. Furthermore, PCR analysis performed on fixed, routinely processed colon biopsies is an excellent diagnostic method for detection of this organism.