Lessons from Mycobacterium avium complex-associated pneumonitis: a case report

ABSTRACT: INTRODUCTION: Mycobacterium avium complex (MAC) is an increasingly recognized cause of pulmonary disease in immunocompetent individuals. An acute form of MAC lung disease, MAC-associated pneumonitis, has generally been associated with the use of hot tubs. There is controversy in the literature about whether MAC-associated pneumonitis is a classic hypersensitivity pneumonitis or is a direct manifestation of mycobacterial infection. CASE PRESENTATION: We report the second case in the literature of MAC-associated pneumonitis not related to the use of hot tubs. The source of MAC in a 52-year-old immunocompetent patient was an intrapulmonary cyst containing numerous acid-fast bacilli. The patient developed disseminated miliary nodules throughout both lung fields. Histological examination of resected lung tissue revealed well-formed, acid-fast negative granulomas composed predominantly of CD4+ T-cells and CD68+ histiocytes. The granulomas were strongly positive for tumor necrosis factor-alpha, a pro-inflammatory cytokine. CONCLUSION: The attempt to classify MAC-associated pneumonitis as either a classic hypersensitivity pneumonitis or a direct manifestation of mycobacterial infection is not particularly useful. Our case demonstrates that MAC-associated pneumonitis is characterized by a vigorous T-helper 1-like, pro-inflammatory, immune response to pulmonary mycobacterial infection. The immunopathology provides a rationale for clinical studies of anti-MAC therapy with the addition of anti-inflammatory agents (for example, corticosteroids) to hasten the resolution of infection and symptoms

Five top stories in anatomic pathology: stories from the faculty at UMass Medical School and UMass Memorial Medical Center, Worcester, Massachusetts

This month\u27s issue of the Archives of Pathology & Laboratory Medicine introduces a new series of special sections featuring relevant and contemporary topics in Anatomic Pathology and Cytopathology, herein referred to as “Five Top Stories.

Extraarticular synovial chondromatosis: review of epidemiology, imaging studies, microscopy and pathogenesis, with a report of an additional case in a child

A rare benign condition of uncertain etiology and pathogenesis, Synovial Chondromatosis (SC) is most often seen intraarticularly in adults but only a handful of cases have been reported extraarticularly in children. Symptoms and physical signs consist of pain, swelling, and osteoarthritic changes related to a mass effect. Here we discuss the case of a 9-year-old boy with documented SC of the knee and critically review the Epidemiology, Clinical Presentation, Gross Anatomy and Microscopic Histopathologic Features as well as the role of Imaging Studies in Diagnosis. In addition, this paper reviews Current Pathogenetic Concepts including the infrequent but distinct possibility of malignant transformation

Necrotizing tracheobronchitis with progressive airflow obstruction associated with paraneoplastic pemphigus

Paraneoplastic pemphigus (PNP) is an autoimmune disease associated with leukemia and non-Hodgkin\u27s lymphoma. A patient with stage IVB poorly differentiated lymphocytic lymphoma developed characteristic upper and lower airway involvement with profound mucocutaneous erosion and tracheobronchial epithelial desquamation. Immunofluorescence testing confirmed autoantibody deposition along the basement membrane of bronchial epithelium. Disruption of the cellular adhesion mechanisms, including desmosomes, hemidesmosomes, and possibly the integrin subunits, is presumed to have led to disruption and desquamation of the tracheobronchial epithelial barrier, severe obstruction of the airways and hypoxia, and possibly bacterial superinfection. As far as can be determined, the feature of airflow obstruction occurring in association with PNP has not been described. Physicians should be aware that these complications of PNP may rapidly lead to hypoxic respiratory failure and death

Transbronchial lung biopsy: can specimen quality be predicted at the time of biopsy

STUDY OBJECTIVES: To determine the bronchoscopist\u27s ability to predict specimen quality at the time of transbronchial biopsy and to determine the influence of biopsy specimen size and alveolar content on diagnostic value. DESIGN: Prospective, blinded, observational analysis. SETTING: Tertiary care academic hospital-based pulmonary practice. PATIENTS: Forty-three adult patients who underwent transbronchial lung biopsy. INTERVENTIONS: Each of 170 biopsy specimens was rated as to likelihood of containing diagnostic tissue, size and ability to float, tissue types present, number of alveoli, and pathologic diagnosis. RESULTS: Fifteen percent of biopsy specimens were small and 40% were large. Seventy-six percent of specimens floated; 61.8% of the 170 biopsy specimens contained abnormal lung tissue; and 14.7% of individual specimens were diagnostic. Fifty-two percent of specimens contained \u3e20 alveoli. Larger biopsy specimens were more likely to contain diagnostic tissue (r=0.29, p=0.001). Cup forceps retrieved smaller pieces of tissue (p=0.007) and were less likely to obtain diagnostic tissue (p=0.06). Physician ratings of specimen quality (mean+/-SD) did not differ between specimens containing normal and abnormal tissue (5.98+/-2.3 vs 5.46+/-5.5; p=0.24) or between specimens containing diagnostic vs nondiagnostic tissue (5.56+/-2.5 vs 6.25+/-2.1; p=0.14). Specimens that floated were no more likely to be diagnostic or abnormal than specimens that sank (

Metastatic papillary thyroid carcinoma to lung diagnosed by bronchoalveolar lavage

The diagnosis of papillary carcinoma of the thyroid metastatic to the lung frequently requires a battery of noninvasive tests. Occasionally, invasive procedures such as open lung biopsy, transthoracic needle biopsy, and transbronchial lung biopsy are employed to confirm the diagnosis. A 31-yr-old woman with papillary thyroid carcinoma treated previously by a near-total thyroidectomy and 131I ablation presented to our clinic with shortness of breath and a clear chest roentgenogram. A post-131I treatment whole body scan revealed widespread 131I pulmonary uptake, and the presence of papillary thyroid cancer was confirmed by bronchoalveolar lavage. We conclude that bronchoalveolar lavage should be considered when tissue confirmation of metastatic papillary carcinoma to the lung is needed. During the evaluation and follow-up of this patient, we were able to determine that metastatic papillary carcinoma to the lung may cause a methacholine bronchoprovocation test to be falsely positive for asthma

Interpreting the histopathology of chronic cough: a prospective, controlled, comparative study

HYPOTHESIS: Trauma from chronic coughing produces airway inflammation similar to diseases causing cough. DESIGN: Prospective, cross-sectional, controlled, clinicopathologic correlation study in four groups: group 1, cough from intrapulmonary diseases; group 2, cough from extrapulmonary diseases; group 3, cough that was unexplained; and group 4, nonsmoking, asymptomatic control subjects. METHODS: Patients with chronic cough underwent a standardized workup including endobronchial biopsies before treatment. Causes were determined by a favorable response to therapy. Bronchial biopsy samples from control subjects were obtained from surgical specimens. RESULTS: There were 24 adult subjects (13 women and 11 men) with mean cough duration of 8.6 +/- 7.4 years (+/- SD). Thirteen patients had cough due to a specific disease: intrapulmonary diseases in 5 patients, and extrapulmonary diseases in 8 patients. Eleven patients had unexplained cough. Compared to control subjects, there was minimal-to-moderate chronic inflammation in all coughers (p \u3c or = 0.0004), in group 1 (p \u3c or = 0.039), group 2 (p = 0.061), and group 3 (p \u3c or = 0.025) diseases that were not correlated with cough duration. There was no difference in type of inflammation, cough duration, or smoking history between groups, nor were there histologic differences between subjects with explained causes of cough compared with unexplained cough. CONCLUSIONS: Our findings suggest that airway inflammation associated with chronic cough, assessed on morphologic appearance and inflammatory cell counting in hematoxylin-eosin-prepared samples, may be due to the trauma of coughing, and the inflammation may be similar to that seen with diseases putatively thought to cause chronic cough. Investigators must be cautious when attributing pathogenic importance to observed inflammatory changes in airways of coughing subjects

Specific History of Heterologous Virus Infections Determines Anti-Viral Immunity and Immunopathology in the Lung

Having previously shown that previous immunity to one virus can influence the host response to a subsequent unrelated virus, we questioned whether the outcome to a given virus infection would be altered in similar or different ways by previous immunity to different viruses, and whether immunity to a given virus would have similar effects on all subsequent infections. In mouse models of respiratory viral infections, immunity to lymphocytic choriomeningitis virus (LCMV), murine cytomegalovirus (MCMV), or influenza A virus enhanced both Th1-type cytokine responses and viral clearance in the lung on vaccinia virus infection. A common pathological feature was the presence of chronic mononuclear infiltrates instead of the acute polymorphonuclear response seen in the infected nonimmune mice, but some pathologies such as enhanced bronchus-associated lymphoid tissue and bronchiolitis obliterans were unique for the immunizing virus, LCMV. Immunity to influenza virus influenced subsequent infections diversely, inhibiting vaccinia virus but enhancing LCMV and MCMV titers and completely altering cytokine profiles. Influenza virus immunity enhanced the mild mononuclear responses usually observed during acute infections with MCMV or LCMV in nonimmune mice, but unique features such as enhanced bronchiolization and mononuclear consolidation occurred during MCMV infection of influenza virus-immune mice. Heterologous immunity induced two patterns of disease outcome dependent on the specific virus infection sequence: improved, if the acute response switched from a neutrophilic to a lymphocytic response or worsened, if it switched from a mild to a severe lymphocytic response. Heterologous immunity thus occurs between many viruses, resulting in altered protective immunity and lung immunopathology, and this is influenced by the specific virus infection sequence