The role of lung biopsy for diagnosis and prognosis of interstitial lung disease in systemic sclerosis: a systematic literature review.

BACKGROUND: The prognostic and theragnostic role of histopathological subsets in systemic sclerosis interstitial lung disease (SSc-ILD) have been largely neglected due to the paucity of treatment options and the risks associated with surgical lung biopsy. The novel drugs for the treatment of ILDs and the availability of transbronchial cryobiopsy provide a new clinical scenario making lung biopsy more feasible and a pivotal guide for treatment. The aim of our study was to investigate the usefulness of lung biopsy in SSc ILD with a systematic literature review (SLR). METHODS: PubMed, Embase and Cochrane databases were searched up to June 30, 2023. Search terms included both database-specific controlled vocabulary terms and free-text terms relating to lung biopsy and SSc-ILD diagnostic and prognosis. The SLR was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA). Studies were selected according to the PEO (population, exposure, and outcomes) framework and Quality assessment of diagnostic accuracy studies (QUADAS) were reported. RESULTS: We selected 14 articles (comprising 364 SSc-ILD patients). The paucity and heterogeneity of the studies prevented a systematic analysis. Diffuse cutaneous SSc was present in 30-100% of cases. Female predominance was observed in all studies (ranging from 64 to 100%). Mean age ranged from 42 to 64 years. Mean FVC was 73.98 (+/-17.3), mean DLCO was 59.49 (+/-16.1). Anti-Scl70 antibodies positivity was detected in 33% of cases (range: 0-69.6). All patients underwent surgical lung biopsies, and multiple lobes were biopsied in a minority of studies (4/14). Poor HRCT-pathologic correlation was reported with HRCT-NSIP showing histopathologic UIP in up to 1/3 of cases. Limited data suggest that SSc-UIP patients may have a worse prognosis and response to immunosuppressive treatment compared to other histopathologic patterns. CONCLUSIONS: The data from this SLR clearly show the paucity and heterogeneity of the studies reporting lung biopsy in SSc ILD. Moreover, they highlight the need for further research to address whether the lung biopsy can be helpful to refine prognostic prediction and guide therapeutic choices.

Significance of connective tissue disease features in idiopathic interstitial pneumonia.

In idiopathic interstitial pneumonia (IIP), the significance of connective tissue disease (CTD) features in the absence of a specific CTD diagnosis remains unclear. We studied the clinical and prognostic utility of a diagnosis of undifferentiated CTD (UCTD) in patients with biopsy-proven IIP. IIP patients undergoing surgical lung biopsy (1979-2005) were studied (nonspecific interstitial pneumonia (NSIP), n = 45; idiopathic pulmonary fibrosis, n = 56). UCTD was considered present when serum autoantibodies were present and symptoms or signs suggested CTD. The relationship between UCTD and NSIP histology was evaluated. A clinical algorithm that best predicted NSIP histology was constructed using a priori variables. The prognostic utility of UCTD, and of this algorithm, was evaluated. UCTD was present in 14 (31%) NSIP and seven (13%) IPF patients. UCTD was not associated with a survival benefit. The algorithm predictive of NSIP (OR 10.4, 95% CI 3.21-33.67; p<0.0001) consisted of the absence of typical high-resolution computed tomography (HRCT) features for IPF and 1) a compatible demographic profile (females aged <50 yrs) or 2) Raynaud's phenomenon. In patients with an HRCT scan not typical for IPF, this algorithm predicted improved survival (hazard ratio 0.35, 95% CI 0.14-0.85; p = 0.02) independent of IIP severity. UCTD is associated with NSIP histology. However, the diagnostic and prognostic significance of UCTD in IIP patients remains unclear.

Marginal decline in forced vital capacity is associated with a poor outcome in idiopathic pulmonary fibrosis.

In therapeutic studies in idiopathic pulmonary fibrosis (IPF), the low prevalence of significant change in pulmonary functional tests (PFTs) has been a major constraint. The prognostic value of "marginal" changes in PFTs in IPF and fibrotic non-specific interstitial pneumonia (NSIP) was evaluated. In patients with biopsy-proven IPF (n = 84) and NSIP (n = 72), forced vital capacity (FVC) and diffusing capacity of the lung for carbon monoxide (D( L,CO)) trends at 6 months were categorised as "significant" (FVC >10%; D(L,CO) >15%) or "marginal" (FVC 5-10%; D(L,CO) 7.5-15%). Proportional hazards analysis and time-dependent receiver operating characteristic methodology were used to examine PFT trends against mortality. In IPF, reductions in FVC were significant in 22 cases (26%) and marginal in 19 cases (23%). Mortality was higher in patients with a significant decline in FVC (hazard ratio (HR) 2.80, 95% CI 1.54-5.06; p<0.001) and those with a marginal decline in FVC (HR 2.31, 95% CI 1.19-4.50; p = 0.01) than in those with stable disease. Progression-free survival was lower when the decline in FVC was marginal than in stable disease (HR 2.34, 95% CI 1.19-4.60; p = 0.01). Marginal changes in D(L,CO) in IPF and marginal changes in FVC and D (L,CO) in fibrotic NSIP did not provide useful prognostic information. Marginal change in FVC in IPF denotes a poor outcome. These findings are applicable to clinical practice and to the selection of patients with more progressive disease for therapeutic studies.

Clinical course and lung function change of idiopathic nonspecific interstitial pneumonia.

Most studies of idiopathic nonspecific interstitial pneumonia (NSIP) have primarily studied mortality. In order to clarify the detailed outcome and prognostic markers in idiopathic NSIP, the clinical course with initial radiological and clinical features was analysed. The clinical course of 83 patients who were classified with idiopathic NSIP (72 fibrotic, 11 cellular; 27 males and 56 females; mean+/-sd age 54.4+/-10.1 yrs) was retrospectively analysed. In fibrotic NSIP, 16 (22%) patients died of NSIP-related causes with a median (range) follow-up of 53 (0.3-181) months. Despite the favourable survival (5-yr 74%), patients with fibrotic NSIP were frequently hospitalised with recurrence rate of 36%. Reduced forced vital capacity at 12 months was a predictor of mortality. On follow-up, lung function was improved or stable in approximately 80% of the patients. The extent of consolidation and ground-glass opacity on initial high-resolution computed tomography correlated significantly with serial changes of lung function, and the presence of honeycombing was a predictor of poor prognosis. During follow-up, eight (10%) patients developed collagen vascular disease. In conclusion, the overall prognosis of fibrotic nonspecific interstitial pneumonia was good; however, there were significant recurrences despite initial improvement and a subset of the patients did not respond to therapy. Some patients developed collagen vascular diseases at a later date.

Sex differences in physiological progression of idiopathic pulmonary fibrosis.

In idiopathic pulmonary fibrosis, incidence is higher in males, and females may have better survival. The aim of the present study was to determine whether the rate of increase in desaturation during serial 6-min walk testing would be greater, and survival worse, for males versus females. Serial changes in the percentage of maximum desaturation area (DA) over 1 yr were estimated using mixed models in 215 patients. DA was defined as the total area above the curve created using desaturation percentage values observed during each minute of the 6-min walk test. Multivariate Cox regression assessed survival differences. Adjusting for baseline DA, 6-min walk distance, change in 6-min walk distance over time and smoking history, the percentage of maximum DA increased by an average of 2.83 and 1.37% per month for males and females, respectively. Females demonstrated better survival overall, which was more pronounced in patients who did not desaturate below 88% on ambulation at baseline and after additionally adjusting for 6-month relative changes in DA and forced vital capacity. These data suggest that differences in disease progression contribute to, but do not completely explain, better survival of females with idiopathic pulmonary fibrosis.

Eosinophilia in bronchoalveolar lavage fluid and architectural destruction are features of desquamative interstitial pneumonia.

AIMS: Desquamative interstitial pneumonia (DIP) is a rare pattern of diffuse parenchymal lung disease known to overlap with respiratory bronchiolitis-interstitial lung disease (RB-ILD). The aim was to review biopsy-proven cases of DIP to investigate further the clinical, imaging and histological features of this disease. METHODS AND RESULTS: Twenty patients fulfilled the pathological criteria: 19 men and one woman with a mean age of 54 years. Clinical features, bronchoalveolar lavage (BAL) data, radiological findings, pathological findings other than criteria, effect of therapy and outcome were examined. The BAL data for 17 cases revealed marked eosinophilia (mean 18%) and moderate neutrophilia (mean 11%). Computed tomography in 17 patients showed peripheral involvement in all cases with a clear margin in 64% and thin-walled cysts in 35% of cases. Additional pathological features were a distinct lobular distribution (70%) and architectural destruction (70%) with cyst formation (55%). Eighteen of the 19 patients (95%) improved under steroid pulse and/or oral therapy. Sixteen subjects (80%) are alive, three died of other diseases and one died of DIP 74 months after the diagnosis. Percent vital capacity increased significantly and new thin-walled cysts appeared in one case. CONCLUSIONS: BAL eosinophilia, lobular distribution and architectural destruction with cyst formation are characteristic features of DIP.

Smoking-related changes in the background lung of specimens resected for lung cancer: a semiquantitative study with correlation to postoperative course.

AIMS: To assess the pathological findings in lobectomy specimens, to correlate them with smoking history and postoperative course and to compare the findings with those in smoking-related interstitial lung disease. METHODS AND RESULTS: Patients who had undergone lobectomy for lung cancer were reviewed. Subjects included 230 non-smokers and 587 smokers, of whom 572 had a known smoking index (SI). They were classified into mild, moderate and heavy smokers. Centrilobular emphysema (CLE), respiratory bronchiolitis, airspace enlargement with fibrosis (AEF), the presence of foci resembling usual interstitial pneumonia pattern (UIP/P) and the rate of postoperative respiratory failure were assessed. The incidence of AEF was 6.5% in mild smokers, and 17.7% in moderate smokers (P < 0.01) with lower lobe predominance. There were significant correlations (P < 0.01) between AEF and CLE and AEF and UIP/P. The rate of respiratory failure after lobectomy was 6%, and 10% in patients having UIP/P with or without AEF, but was not seen in patients with AEF alone (P < 0.01). CONCLUSIONS: AEF is an important smoking-related change in the lung that appears to correlate with the smoking history, and its distinction from UIP/P may be important.

Focal interstitial CC chemokine receptor 7 (CCR7) expression in idiopathic interstitial pneumonia.

BACKGROUND/AIMS: Idiopathic interstitial pneumonias (IIPs) are a diverse grouping of chronic pulmonary diseases characterised by varying degrees of pulmonary fibrosis. The triggers of the fibroproliferative process in IIP remain enigmatic but recent attention has been directed towards chemokine involvement in this process. METHODS: The expression of two chemokine receptors, CCR7 and CXCR4, and their respective ligands, CCL19, CCL21, and CXCL12, were examined in surgical lung biopsies (SLBs) from patients with IIP. Transcript and protein expression of these receptors and their ligands was compared with that detected in histologically normal margin SLBs. RESULTS: CCR7 and CXCR4 were detected by gene array and real time polymerase chain reaction analysis and CCR7, but not CXCR4, expression was significantly raised in usual interstitial pneumonia (UIP) relative to biopsies from patients diagnosed with non-specific interstitial pneumonia (NSIP) or respiratory bronchiolitis/interstitial lung disease (RBILD). CCR7 protein was expressed in interstitial areas of all upper and lower lobe UIP SLBs analysed. CCR7 expression was present in 50% of NSIP SLBs, and CCR7 was restricted to blood vessels and mononuclear cells in 75% of RBILD SLBs. Immune cell specific CXCR4 expression was seen in IIP and normal margin biopsies. CCR7 positive areas in UIP biopsies were concomitantly positive for CD45 (the leucocyte common antigen) but CCR7 positive areas in all IIP SLBs lacked the haemopoietic stem cell antigen CD34, collagen 1, and alpha smooth muscle actin. CONCLUSION: This molecular and immunohistochemical analysis showed that IIPs are associated with abnormal CCR7 transcript and protein expression.

p53 protein accumulates frequently in early bronchial neoplasia.

p53 mutations are common in human lung cancer and frequently generate levels of p53 protein that are detectable by immunohistochemistry. For this reason, p53 protein accumulation is a candidate biomarker, but little is known about its timing or frequency in multistage bronchial carcinogenesis. We studied human lung tissues containing preinvasive squamous neoplasms from 34 donors with and without lung cancer. Nuclear p53 protein was present in 0% of normal mucosas, 6.7% of squamous metaplasias, 29.5% of mild dysplasias, 26.9% of moderate dysplasias, 59.7% of severe dysplasias, 58.5% of carcinomas in situ, 67.5% of microinvasive carcinomas, and 79.5% of invasive tumors. These data indicate that (a) p53 protein accumulates in about 30% of the earliest recognized neoplastic lesions (i.e., mild dysplasia), (b) there is an increasing frequency of p53 protein accumulation starting with mild dysplasia, and (c) p53 protein accumulates infrequently in normal or metaplastic mucosa. In a subset of six patients whose most advanced lesion was carcinoma in situ without evidence of invasive cancer, p53 protein was detected in 0% of normal mucosas, 8.3% of squamous metaplasias, 37.5% of mild dysplasias, 12.5% of moderate dysplasias, 93.8% of severe dysplasias, and 55% of carcinoma in situ lesions. These data show clearly that p53 alterations can occur before invasion and suggest that the frequency is similar to that observed in the full series. Since two-thirds or more of lung cancers have p53 alterations, the timing and frequency of p53 protein accumulation make the p53 tumor suppressor gene an attractive marker for early diagnosis and evaluation of chemoprevention agents.

Allelic deletion analysis of the FHIT gene predicts poor survival in non-small cell lung cancer.

The fragile histidine triad (FHIT) gene at chromosome 3p14.2 is a candidate tumor suppressor gene linked to cancers of the lung, breast, colon, pancreas, and head and neck. Reports of frequent allelic deletion and abnormal transcripts in primary lung tumors plus recent evidence that it is targeted by tobacco smoke carcinogens suggest that it plays an important role in lung carcinogenesis. Non-small cell lung carcinoma still maintains a poor 5-year survival rate with the stage of disease at presentation as a major determinant of prognosis. We examined for allelic deletion at the FHIT locus in a series of 106 non-small cell lung carcinomas for which a full clinical, epidemiological, and 5-year survival profile was available. We found an allelic deletion frequency of 38% at one or two intragenic microsatellites. Allelic deletion of FHIT was related to tumor histology with 4 of 20 adenocarcinomas (20%) displaying loss of heterozygosity (LOH) compared with 12 of 22 (55%) nonadenocarcinomas (P = 0.03). We found that 63% of tumors with LOH of FHIT also had p53 missense mutations whereas only 26% with LOH had wild type p53 negative sequence (P = 0.02). We also found a significant trend toward poorer survival in patients with LOH of at least one locus of the FHIT gene (log rank, P = 0.01). This survival correlation is independent of tumor stage, size, histological subtype, degree of differentiation, and p53 mutation status. Our data support the hypothesis that the loss of the FHIT contributes to the molecular pathogenesis of human lung cancer and is an indicator of poor prognosis.

Histologic conversion in the non-Hodgkin's lymphomas.

Between July 1, 1971 and December 31, 1978, 150 patients with favorable subtypes of non-Hodgkin's lymphoma [nodular poorly differentiated lymphocytic (NLPD), nodular mixed, or diffuse well differentiated lymphocytic] were entered into prospective randomized clinical trials at Stanford University. Treatments included involved field, total lymphoid, or whole body irradiation, single alkylating agent chemotherapy, combination chemotherapy with cyclophosphamide, vincristine and prednisone (CVP) or with cyclophosphamide, vincristine, procarbazine, and prednisone (C-MOPP), or various combinations of chemotherapy and irradiation. The initial complete response rate (CR) was 79%. Among patients who achieved a CR, 31% later relapsed. There were 78 patients who either failed to achieve a CR or achieved a CR and later relapsed. Histologic conversion (change from initially favorable to an unfavorable subtype of non-Hodgkin's lymphoma) was documented in 22/78 patients (28%). However, the actuarial risk for conversion was actually much greater (60% at 8 yr). The median time to documentation of conversion was 51 mo. The most common type of histologic conversion was from NLPD to diffuse histiocytic lymphoma. Documented histologic conversion was often associated with a more aggressive clinical behavior of the lymphoma, and the median survival after conversion was less than 1 yr. However, those patients who achieved a CR after conversion had a more favorable outcome (actuarial survival 75% at 5 yr). No specific risk factors predictive of histologic conversion could be identified.

The role of radiation therapy in the management of stage III follicular lymphomas.

Between 1961 and 1982, 66 patients with stage III follicular small cleaved (FSC) and follicular mixed small cleaved and large cell (FM) lymphoma were treated at Stanford University. Treatment consisted of total-lymphoid irradiation (TLI) to a total dose of about 4,000 rad in 61 patients or whole-body irradiation (WBI) followed by boost irradiation to sites of involvement in five patients. In addition, 13 patients treated with TLI received adjuvant chemotherapy, consisting of six cycles of cyclophosphamide, vincristine, and prednisone (CVP). Median follow-up was 9.6 years. Kaplan-Meier actuarial survival at five, ten, and 15 years was 78%, 50%, and 37%, respectively. Freedom from relapse at five and ten years was 60% and 40% with no relapses after ten years. In a prospective randomized study of 16 patients who all underwent staging laparotomy comparing TLI with or without adjuvant chemotherapy with CVP, there was no significant difference in either survival or freedom from relapse between the two groups. Patients with limited stage III disease (without B symptoms, less than five sites of involvement, and maximum size of disease less than 10 cm) had an excellent prognosis with a 15-year survival and freedom from relapse of 100% and 88%, respectively. Radiation therapy may be a potentially curative modality in patients with stage III follicular lymphomas.

Anti-p53 antibodies in sera from patients with chronic obstructive pulmonary disease can predate a diagnosis of cancer.

Serum anti-p53 antibodies (p53-Abs) may be surrogate markers for both p53 alterations and preclinical cancer. Ancillary to a prospective trial to abate progressive development of clinical stages of chronic obstructive pulmonary disease, we conducted a retrospective, nested case-control study. Twenty-three cases were diagnosed with cancer during the trial. Enzyme immunoassay, immunoblotting, and immunoprecipitation were used to detect p53-Abs in serum, immunohistochemistry (IHC) to detect p53 accumulation, and single-strand conformation polymorphism and DNA sequencing to detect p53 mutations in tumor samples. p53-Abs were detected by three types of assays in five (23%) of the cancer patients, 80% of whom had detectable p53-Abs before diagnosis: 2 lung cancers (7 and 6 months before), 1 prostate cancer (11 months), and 1 breast cancer (5 months). Four Ab-positive patients had IHC-positive tumors. Two of 4 Ab-positive patients and 2 of 14 Ab-negative had p53 missense mutations or base pair deletion and IHC-positive tumors. The 44 noncancer COPD controls, matched with the cancer cases for age, gender, and smoking habits, were negative for p53-Abs. These results indicate that p53-Abs may facilitate the early diagnosis of cancer in a subset of smokers with chronic obstructive pulmonary disease who are at an increased cancer risk.

Organizing pneumonia. Features and prognosis of cryptogenic, secondary, and focal variants.

BACKGROUND: Organizing pneumonia (OP) is a non-specific response to many types of lung injury. Clinicians frequently encounter pathology reports of OP in patients with no underlying condition (cryptogenic OP, also known as BOOP or bronchiolitis obliterans OP) or in association with drugs or nonpulmonary disease. The goals of this study are to describe the clinical course and outcomes in patients with 3 clinical variants of OP. METHODS: A retrospective study of patients with OP seen at the Mayo Clinic, Rochester, Minn, from January 1, 1984, through June 30, 1994, was conducted. Initial features were obtained from medical records. Chest radiographs and pathology specimens were reviewed for this study. Resolution, relapse, and survival were obtained from medical records and a follow-up patient questionnaire. RESULTS: Seventy-four patients had pathologically confirmed OP. Organizing pneumonia was classified into 3 clinical groups: symptomatic cryptogenic OP; symptomatic OP related to underlying hematologic malignant neoplasm, collagen vascular disease, or drugs (secondary OP); and asymptomatic OP presenting as a focal nodule (focal OP). Thirty-seven patients (50%) had cryptogenic OP and 27 patients (36%) had secondary OP. No difference was found between cryptogenic and secondary OP in type or severity of symptoms, signs, laboratory and pulmonary function tests, or radiologic or pathologic findings. Corticosteroids were given at a similar initial dose (prednisone, about 50 mg/d). Resolution of symptoms was more frequent in patients with cryptogenic OP than those with secondary OP. Relapse was infrequent in both of these groups. Five-year survival was higher in patients with cryptogenic OP (73%) than in secondary OP (44%), and respiratory-related deaths were more frequent in patients with secondary OP. Organizing pneumonia was an asymptomatic focal rounded opacity in 10 patients (14%), most often detected on chest radiograph and diagnosed on lung biopsy done for suspicion of lung cancer. Patients with focal OP required no treatment and had no relapse or respiratory-related deaths. CONCLUSIONS: Clinical classification of OP is useful to predict clinical course and outcome. Cryptogenic OP most often was a symptomatic bilateral lung process that had an overall favorable prognosis with prolonged corticosteroid therapy. Patients with secondary OP had a high mortality rate when the disease was associated with predisposing conditions or drugs. Patients with asymptomatic focal OP had an excellent prognosis.

The lung in inflammatory bowel disease.

Respiratory involvement in patients with inflammatory bowel disease (IBD) has been reported mainly since 1976. This form of involvement should clearly be separated from interstitial lung disease due to sulfasalazine or mesalamine, although the distinction may be difficult in some cases. We report the data of an ongoing Registry containing 33 cases (23 cases receiving no drug therapy) with ulcerative colitis or, less often, Crohn's disease, who developed varied bronchopulmonary problems. In several cases, the exact diagnosis and the relation of the bronchopulmonary disease to IBD had not been established for many years, thus delaying effective treatment with steroids. In most cases (28/33), respiratory involvement followed the onset of IBD (8 of these 28 cases were postcolectomy), and in the remainder, respiratory manifestations predated the IBD. Patterns of involvement included: 1) Airway inflammation, in the form of subglottic stenosis, chronic bronchitis, severe chronic bronchial suppuration, bronchiectasis, and chronic bronchiolitis. In cases with large airway involvement, endoscopy showed exuberant inflammatory tissue in the airways and narrowing of tracheal and/or bronchial lumen. Histologically, airways were heavily infiltrated by a dense aggregate of inflammatory cells, and there were mucosal ulcerations. 2) Varied patterns of interstitial lung disease, mainly bronchiolitis obliterans with organizing pneumonia, and pulmonary infiltrates and eosinophilia. (3) Miscellaneous other forms of involvement including striking neutrophilic necrotic parenchymal nodules (corresponding histologically to sterile aggregates of neutrophils), and serositis. Steroids were very effective in the majority of cases. Inhaled steroids were of durable benefit in patients with chronic bronchitis, but less often so in those with chronic bronchial suppuration, bronchiectasis, or chronic bronchiolitis. Steroids administered orally led to marked improvement in patients with interstitial lung disease and necrotic nodules, but lacked effectiveness in several patients with severe airway inflammation or chronic bronchiolitis. Intravenous steroids were required in the initial management of life-threatening complications such as asphyxiating subglottic stenosis or extensive interstitial lung disease. Bronchial lavages with methylprednisolone were effective in some patients with severe airway inflammation. Patients with IBD can develop varied inflammatory complications in the lung, and a sizable fraction of these complications is steroid-sensitive.

p53 mutations and occupational exposures in a surgical series of lung cancers.

p53 mutations are frequent in malignant lung tumors. Of 88 surgically treated lung cancers from cigarette smokers previously evaluated for p53 mutations, 45 tumors (51.1%) had mutations in exons 5-8 (D. G. Guinee, Jr. et al., Carcinogenesis (Lond.), 16: 993-1002, 1995). We report here the examination of 13 occupational exposures and 13 high-risk occupations in relation to these p53 mutations. Two molecular abnormalities were associated with occupational exposures: (a) G:C-->T:A transversions on the coding (nontranscribed) strand (n = 13) were associated with chromate exposure and employment in the metal industry (P < 0.05) and marginally associated with nickel exposure (P = 0.056); and (b) G:C-->A:T transitions at non-CpG sites (n = 9) were associated with work in the petrochemical industry (P = 0.05). No association was found between p53 mutations and gender, cigarette pack-years, tumor histology, age at diagnosis, or family history of lung cancer. Because all three chromate-exposed subjects had large cell carcinomas exhibiting G: C-->T:A coding-strand transversions, follow-up of a cohort with this exposure should clarify the association with the p53 gene.

Radiation therapy for diabetes insipidus caused by Langerhans cell histiocytosis.

Hypothalamic-pituitary radiation therapy has been the standard treatment for the diabetes insipidus of Langerhans cell histiocytosis. The goal of this study was to assess the role of radiation therapy in Langerhans cell histiocytosis-associated diabetes insipidus and to compare the results with nonirradiated controls. Forty-seven patients with pathologically confirmed Langerhans cell histiocytosis were diagnosed with diabetes insipidus between 1950 and 1989 and were treated at the Mayo Clinic. These patients were divided into two groups on the basis of treatment for the diabetes insipidus: The first group (radiation group) included 30 patients (28 of whom were evaluable for response) who received hypothalamic-pituitary radiation therapy, and the second group (control group) included 17 patients who did not. A partial response to treatment was defined as a reduction in vasopressin dosage or improvement in computed tomography (CT) or magnetic resonance imaging (MRI). A complete response was defined as no further need for vasopressin therapy or normalization of CT or MRI. End points analyzed included treatment response, patient characteristics, morbidity, dose-response relationship, and survival. Patient characteristics of the two groups were similar except for age and lung involvement, both of which were significantly less in the radiation group. Thirty-six percent of patients (10 of 28) in the radiation group responded to hypothalamic-pituitary radiation therapy (22% complete response and 14% partial response), whereas none in the control group responded. Five of the six complete responders were irradiated within 14 days of the diagnosis of diabetes insipidus. The mean dose used in the responding and nonresponding patients was 11.2 and 10 Gy, respectively. Three of five patients (60%) treated with more than 15 Gy responded compared to seven of 23 (30%) treated with less than 15 Gy. Eight of the 10 responders (80%), compared to 16 of 35 nonresponders (46%), were female. Only one in 20 patients with concomitant lung histiocytosis responded. Complications of therapy may include insufficiency in other hypothalamic-pituitary axes in the treated patients. Actuarial survivals at 5, 10, 20, and 40 years for the entire group were 80%, 78%, 75%, and 65%, respectively, with a median follow-up in living patients of 14.7 years.

Malakoplakia. Two unusual cases which presented diagnostic problems.

Two unusual cases of malakoplakia are presented. Both cases occurred outside the urinary tract (retroperitoneum and anus) and were diagnostic problems due to the paucity of Michaelis-Guttman bodies. One case mimicked a retroperitoneal malignant fibrous histiocytoma and the other a common perianal abcess.

Histologic diagnosis of extrinsic allergic alveolitis.

Twenty-seven patients with open-lung biopsy findings consistent with extrinsic allergic alveolitis (hypersensitivity pneumonitis) were studied. In only one case had the diagnosis been considered prior to the biopsy. Among the 27 patients, a causative exposure was subsequently identified in 10, and no apparent cause could be found in the remaining 17. The prognosis for the entire group was good; all 10 patients in whom an exposure was found and 13 of 17 without causative exposure are alive without progressive lung disease.

Pulmonary histology for the surgical pathologist.

This is a review of the variety of pulmonary histologic artifacts and incidental findings that may come to the attention of the surgical pathologist. In some cases, these may lead to an erroneous diagnosis; in others, they may obscure the diagnosis. The following groups of lesions are discussed: artifacts seen in biopsy and resection material, site-specific changes commonly encountered, incidental findings and structures seen in biopsy and resection material, and age-related changes. A short review of normal histology is included for perspective and a discussion of the abnormal biopsy that appears normal on first review is presented.