Mediastinal hibernoma simulates a malignant lesion on dual time point FDG imaging.

Dual time point 2-deoxy-2-[18F] fluoro-d-glucose (FDG) positron emission tomography (PET) imaging has been shown to be useful in helping differentiate benign from malignant lesions. An enhancing mediastinal mass of fat and water density was incidentally detected on computed tomography (CT) in a patient being evaluated for thoracic trauma. He subsequently underwent dual time point FDG PET/CT imaging which revealed a significant rise in standard uptake value (SUV) within the lesion over time, favoring a malignant etiology. Biopsy proved the lesion to represent a hibernoma, an uncommon benign fatty tumor. This case exemplifies the complexity of tissue metabolic properties, and the difficulty in establishing absolute criteria for benign and malignant processes.

Parkinson's disease and megacolon: concentric hyaline inclusions (Lewy bodies) in enteric ganglion cells.

Concentric hyaline inclusions (Lewy bodies), found in the cytoplasm of pigmented and nonpigmented neurons, are considered characteristic of idiopathic Parkinson's disease. The finding of cytoplasmic inclusions identical to Lewy bodies in ganglion cells of the colonic myenteric plexus in a patient with idiopathic Parkinson's disease and acquired megacolon suggests primary involvement of the enteric nervous system by Parkinson's disease.

Disseminated Pneumocystis carinii infection in a patient with acquired immunodeficiency syndrome.

Pneumocystis carinii, a frequent cause of pneumonia in immunocompromised patients, rarely disseminates to involve other organs. This report describes a patient with acquired immunodeficiency syndrome and pneumocystis pneumonia in whom extrapulmonary P. carinii infection was diagnosed on duodenal and esophageal endoscopic biopsy specimens. Autopsy revealed dissemination to multiple organs.

Bronchocentric mycosis occurring in transplant recipients.

Although a variety of long-term, probably immunologically induced pulmonary changes have been described in recipients of both combined heart-lung and bone marrow transplantation, pulmonary infections continue to remain causes of significant morbidity and mortality as well. Herein we describe three patients (two heart-lung and one bone marrow transplant recipient) who had bronchocentric granulomatous mycosis, a tissue manifestation of fungal infection not previously described in the setting of a transplant host. Although one patient was being treated successfully with antifungal agents for his mucormycosis, two other patients eventually died of invasive aspergillosis. This emphasizes that although this process is histologically somewhat similar to bronchocentric granulomatosis, a high index of suspicion for infection needs to be maintained when this pathologic process is identified in a transplant host.

Effect of single-dose rapamycin-based immunosuppression on the development of cardiac allograft vasculopathy.

BACKGROUND: Cardiac allograft vasculopathy is the major cause of graft loss more than 1 year after transplantation. Daily rapamycin dosing has been shown to inhibit arterial intimal thickening caused by both alloimmune and mechanical injury. The combination of a single preoperative dose of rapamycin with a short (7 day) course of cyclosporine A has been shown to extend cardiac allograft survival, but its effects on the development of cardiac allograft vasculopathy has not been reported. METHODS: The ACI (RT1(a)) to Lewis (RT1(1)) heterotopic cardiac allograft model was used to assess the development of cardiac allograft vasculopathy and rejection. Treatment groups included nonimmunosuppressed control, cyclosporine A, cyclosporine A/donor-specific transfusion, and rapamycin/cyclosporine A. RESULTS: The addition of a single preoperative dose of rapamycin to a short course of cyclosporine A significantly reduced the prevalence of cardiac allograft vasculopathy in small (1.18 +/- 1.4 versus 0.05 +/- 0.3; p = 0.0001), medium (2.05 +/- 1.09 versus 0.26 +/- 0.62; p = 0.0001), and large (2.57 +/- 0.84 versus 1.43 +/- 1.2; p = 0.0008) vessels when compared with that in allografts treated with a single preoperative donor-specific transfusion and the same cyclosporine A schedule. Cardiac allograft vasculopathy did not develop in the nonimmunosuppressed control grafts or the group treated with cyclosporine A alone, because of the short survival times in these groups. In addition, there was a reduction of the rejection score in the rapamycin-treated allografts compared with that in the other treatment groups (4.0 +/- 0.0 versus 3.25 +/- 0.5; p = 0.0006). CONCLUSIONS: These results suggest that a single preoperative dose of rapamycin is efficacious in preventing the development of cardiac allograft vasculopathy, and continued immunosuppression with rapamycin may be unnecessary.

Detection of cytomegalovirus in lung allografts. Comparison of histologic and immunohistochemical findings.

Although the histologic manifestation of cytomegalovirus (CMV) is usually characteristic intracellular inclusions and cytomegaly, some investigators, using immunohistochemical or in situ hybridization techniques, have demonstrated the presence of histologically occult infections in certain tissues. A series of lung biopsy specimens from pulmonary transplant recipients were studied using a monoclonal antibody (CCH2) to CMV early viral antigen and the results were compared with routine histologic findings. Occult infection could not be demonstrated in any of these cases. These results may reflect the relative sensitivity of the monoclonal antibody used in this study, although other possible factors are discussed. The results suggest that, in lung allograft biopsy specimens, immunohistochemical analysis using monoclonal antibody CCH2 is not likely to increase significantly the yield of positive cases compared with examination of multiple levels of hematoxylin-and-eosin-stained sections. Additional studies are needed to compare the sensitivity of monoclonal antibodies to CMV antigens using a variety of sampling techniques and clinical settings.

CD5 immunoreactivity of epithelial cells in thymic carcinoma and CASTLE using paraffin-embedded tissue.

Because the histologic features may resemble those of other mediastinal malignancies, thymic carcinoma can be difficult to diagnose, particularly if the primary site is uncertain. In an effort to facilitate this diagnosis, the authors have evaluated the use of immunohistochemistry with an antibody to CD5 (NCL-CD5). Nine thymic carcinomas, 15 thymomas, 8 lymphomas, 10 poorly differentiated lung carcinomas, 10 breast carcinomas, 1 mediastinal seminoma, and 1 thyroid carcinoma showing thymus-like differentiation (CASTLE) were studied. Four of 9 poorly differentiated carcinomas of the thymus were CD5 positive. The one CASTLE was CD5 positive. All other tumors were negative. CD5-positive lymphocytes were internal controls in every case. CD5 labels some thymic carcinomas in paraffin-embedded tissue, whereas other tumors studied were negative. CD5 immunoreactivity of CASTLE appears to support thymic derivation of this tumor.

Nodular bleomycin toxicity.

Pulmonary interstitial fibrosis, a well-known toxic effect of bleomycin therapy, usually presents radiographically as diffuse reticularity. The authors report an unusual case of biopsy-proven bleomycin toxicity that presented as pulmonary nodules mimicking metastatic tumor. The histologic findings resembled those seen in the diffuse form of toxicity but notably also included foci of bronchiolitis obliterans.

Improved oxygenation with exogenous surfactant administration in experimental meconium aspiration syndrome.

Fifteen adult New Zealand white rabbits were used to determine if exogenous surfactant immediately improves oxygenation in experimental meconium aspiration syndrome (MAS). They were ventilated with 100% O2 before insufflating 3 mL/kg of 40% filtered meconium. Arterial blood gases, dynamic lung compliance (CLdyn) and resistance (RL) were monitored for 2 hours before and 1 hour after the intratracheal administration of calf lung surfactant extract or air placebo. The arterial/alveolar O2 tension ratio [P (a/A)O2] increased 133% within 1 hour of surfactant therapy but CLdyn did not change. The increase of RL was comparable in the surfactant and control groups after meconium instillation. A further increase of 44% in RL occurred after surfactant administration with no change in the controls. Qualitative histologic analysis confirmed the presence of alveolar meconium as well as inflammation and atelectasis. Persistently elevated RL suggested airway obstruction in both groups throughout the study. Most likely no increase in CLdyn occurred with surfactant administration or it could not be detected because it was measured only with ventilator-induced breaths and ventilator settings were held constant. In the face of airway obstruction CLdyn is an inadequate reflection of pulmonary elasticity. We conclude that exogenous surfactant therapy improves oxygenation in this model of MAS. Further studies are needed to understand the mechanism of this improvement.

Primary carcinoid tumor of the bladder arising beneath an inverted papilloma.

We describe a 54-year-old woman with a primary carcinoid tumor of the bladder arising beneath an inverted papilloma diagnosed by light microscopy and immunohistochemical studies. After the patient complained of hematuria and voiding difficulties, a polypoid mass was detected during cystoscopy and removed for examination. The distinctive histologic features of an inverted papilloma were readily identified. The characteristic pattern of a carcinoid tumor was confirmed with immunohistochemical studies.

Bronchogenic cyst: a case report emphasizing the role of magnetic resonance imaging.

The article describes a patient with a right paratracheal bronchogenic cyst in whom the preoperative diagnosis was unclear. The fluid component of the cyst was not readily apparent by CT or T1-weighted MR images. Very intense signal on T2-weighted MR images suggested a cystic lesion. Inhomogeneities evident on MR but not CT images provided further soft tissue characterization. These soft tissue elements correlated with a macroscopic ring of hyaline cartilage in the resected specimen. The usefulness of MRI for the differential diagnosis of mediastinal tumors is discussed.

Fine-needle aspiration cytology of localized fibrous tumor of pleura.

Fine-needle aspiration (FNA) biopsy findings are presented in three cases of localized fibrous tumor of pleura (LFTP). Clinically, two of the tumors behaved benignly, although one showed frequent mitoses and foci of necrosis. The third tumor exhibited local aggressiveness as evidenced by rib destruction. Cytologically, these tumors exhibited a wide range of cellularity, composed mainly of small, bland oval to spindle cells with moderate numbers of stripped nuclei. Small bits of collagen were seen in the smears. In all cases, cell blocks were instrumental in making the diagnosis. Previous cytologic descriptions of the tumor are briefly reviewed and the cytologic differential diagnosis is discussed. The peripheral location of this uncommon tumor makes it an ideal target for FNA biopsy.

Cystosarcoma phyllodes of the breast: histologic features, flow cytometric analysis, and clinical correlations.

The histologic features of 187 cases of cystosarcoma phyllodes of the breast were reviewed. The tumors were divided into histologically benign, borderline, and malignant categories. Correlation with clinical outcome was available in 100 cases. Overall rate of local recurrence was 28% (benign, 27%; borderline, 32%; malignant, 26%). Metastases occurred in eight of 100 cases (two borderline and six malignant). Although no histologic features were predictive of local recurrence, stromal overgrowth, mitotic rate greater than 15 per 50 high-power fields, and cytologically atypical stromal cells characterized seven of the eight tumors that metastasized. These features were not evident in the eighth case. Flow cytometric analysis of eight tumors (four benign, two borderline, and two malignant) showed discordance between histology and DNA content in three cases. There was slightly better correlation of histology and S-phase fractions. Based on these results demonstrating the difficulty in predicting clinical outcome, wide local excision remains an appropriate initial method of treatment. Simple mastectomy may be necessary for very large tumors and should be considered in histologically malignant tumors and cases with multiple recurrences, since some recurrent tumors in this series showed increasingly unfavorable histologic features.

CT detection of calcified nodal metastases of lung adenocarcinoma.

Computed tomography of a right middle lobe mass showed no evidence of calcification. Focal calcification in the right midhilar and subcarinal regions was presumed to be granulomatous. Thoracotomy revealed a partially psammomatous adenocarcinoma of lung and dense psammomatous deposits of adenocarcinoma in calcified regional lymph nodes.

Obstructive granulomatous bronchiolitis due to Mycobacterium avium complex in an immunocompetent man.

While the development of pulmonary disease due to Mycobacterium avium complex (MAC) infection is most commonly associated with underlying predisposing factors, this organism occasionally causes symptomatic disease in otherwise normal individuals. Patients with MAC pulmonary disease most often present with cavitating granulomas, but a spectrum of pathologic changes has been described. The authors present a case of MAC pulmonary disease in an immunocompetent, middle-aged man with no identified predisposing factors. The diagnostic biopsy disclosed the unusual finding of noncaseating granulomas with predominant involvement of bronchioles, corresponding to the patient's obstructive and restrictive pulmonary dysfunction.

Bronchial carcinoid tumors: assessment with CT of location and intratumoral calcification in 31 patients.

Bronchial carcinoid tumors (BCT) have long been regarded as predominantly central and rarely calcified. The authors retrospectively reviewed computed tomographic (CT) findings in 31 patients (thin-section CT studies in 18) who were seen at their institution with the histopathologic diagnosis of BCT (27 typical, four atypical) during the years 1978-1989. Eighteen BCT (58%) were central and 13 (42%) peripheral, with peripheral defined as located more than 2 cm distal to the origin of the appropriate segmental bronchus. CT scans revealed varied patterns of calcification in seven (39%) of the 18 central BCT and in one (8%) of the 13 peripheral BCT (P less than .1); overall, CT scans revealed calcification in eight (26%) of the BCT. The eight calcified tumors were each of the typical histopathologic type. Peripheral BCT (42%) were nearly as common as central BCT (58%), and CT detection of calcification in BCT was not uncommon (39% of central lesions; 26%, overall).

Does exhaustive search for microcalcifications improve diagnostic yield in stereotactic core needle breast biopsies?

Stereotactic core needle biopsy (SCNB) of the breast is a cost-effective alternative to needle localization biopsy for the diagnosis of mammographic calcifications. We questioned whether an exhaustive search for calcium in the small samples obtained in SCNB yields more diagnostic information than that obtained with examination of a standard number of sections. We retrospectively reviewed 168 specimens from 123 patients with mammographic calcifications, including cases in which radiographic suspicion ranged from low to high. Microcalcifications were identified on three initial levels in 112 specimens. Additional sections were examined in 50 specimens. The final diagnosis differed from the diagnosis based on three levels in 11/50 cases (22%). In 6/50 (12%), complete sectioning yielded a specific diagnosis. The increase in technical cost associated with the additional levels was 414% per case. We conclude that exhaustive searching for microcalcifications in SCNB yields a small increase in specific diagnostic information and a high technical cost. In individual cases, the additional information may be critical for appropriate patient management.

Hemorrhagic cystitis associated with herpes simplex virus.

A 45-year-old man presented with hemorrhagic cystitis and was found to have herpes simplex infection of the bladder by biopsy, immunohistochemistry and in situ hybridization. The patient had no clinical evidence of immunosuppression or disseminated infection. Although viral etiologies of hemorrhagic cystitis are recognized, to our knowledge only 4 cases of hemorrhagic cystitis due to herpes simplex virus have been reported.