Herpes simplex virus bronchiolitis in a cannabis user

Herpes simplex virus (HSV) lower respiratory tract infections in adults are uncommon. We present a case of HSV bronchiolitis and pneumonitis in an immunocompetent individual, likely linked to chronic habitual marijuana use and a herpetic orolabial ulcer. The case serves as a reminder to consider HSV as a potential unusual cause of lower respiratory tract infection/inflammation in individuals with chronic habitual marijuana use.

Guidelines for pathologic diagnosis of malignant mesothelioma: 2012 update of the consensus statement from the International Mesothelioma Interest Group

CONTEXT

Malignant mesothelioma (MM) is an uncommon tumor that can be difficult to diagnose.

OBJECTIVE

To provide updated practical guidelines for the pathologic diagnosis of MM.

DATA SOURCES

Pathologists involved in the International Mesothelioma Interest Group and others with an interest in the field contributed to this update. Reference material includes peer-reviewed publications and textbooks.

CONCLUSIONS

There was consensus opinion regarding (1) distinction of benign from malignant mesothelial proliferations (both epithelioid and spindle cell lesions), (2) cytologic diagnosis of MM, (3) key histologic features of pleural and peritoneal MM, (4) use of histochemical and immunohistochemical stains in the diagnosis and differential diagnosis of MM, (5) differentiation of epithelioid MM from various carcinomas (lung, breast, ovarian, and colonic adenocarcinomas, and squamous cell and renal cell carcinomas), (6) diagnosis of sarcomatoid mesothelioma, (7) use of molecular markers in the diagnosis of MM, (8) electron microscopy in the diagnosis of MM, and (9) some caveats and pitfalls in the diagnosis of MM. Immunohistochemical panels are integral to the diagnosis of MM, but the exact makeup of panels used is dependent on the differential diagnosis and on the antibodies available in a given laboratory. Immunohistochemical panels should contain both positive and negative markers. It is recommended that immunohistochemical markers have either sensitivity or specificity greater than 80% for the lesions in question. Interpretation of positivity generally should take into account the localization of the stain (eg, nuclear versus cytoplasmic) and the percentage of cells staining (>10% is suggested for cytoplasmic membranous markers). These guidelines are meant to be a practical reference for the pathologist.

Human airway contraction and formoterol-induced relaxation is determined by Ca2+ oscillations and Ca2+ sensitivity

The etiology of airway hyperresponsiveness associated with asthma requires an understanding of the regulatory mechanisms mediating human airway smooth muscle cell (SMC) contraction. The objective of this study was to determine how human airway SMC contraction (induced by histamine) and relaxation (induced by formoterol) are regulated by Ca(2+) oscillations and Ca(2+) sensitivity. The responses of human small airways and their associated SMCs were studied in human lung slices cut from agarose-inflated lungs. Airway contraction was measured with phase-contrast video microscopy. Ca(2+) signaling and Ca(2+) sensitivity of airway SMCs were measured with two-photon fluorescence microscopy and Ca(2+)-permeabilized lung slices. The agonist histamine induced contraction of human small airways by stimulating both an increase in intracellular Ca(2+) concentration in the SMCs in the form of oscillatory Ca(2+) waves and an increase in Ca(2+) sensitivity. The frequency of the Ca(2+) oscillations increased with histamine concentration, and correlated with increased contraction. Formoterol induced airway relaxation at low concentrations by initially decreasing SMC Ca(2+) sensitivity. At higher concentrations, formoterol additionally slowed or inhibited the Ca(2+) oscillations of the SMCs to relax the airways. The action of formoterol was only slowly reversed. Human lung slices provide a powerful experimental assay for the investigation of small airway physiology and pharmacology. Histamine induces contraction by simultaneously increasing SMC Ca(2+) signaling and Ca(2+) sensitivity. Formoterol induces long-lasting relaxation by initially reducing the Ca(2+) sensitivity and, subsequently, the frequency of the Ca(2+) oscillations of the airway SMCs.

Translocation (16;20)(p11.2;q13). sole cytogenetic abnormality in a unicameral bone cyst

We report the results of cytogenetic analysis of a case of unicameral bone cyst with a t(16;20(p11.2;q13) present as the sole abnormality. To our knowledge, this is only the second report of a cytogenetically characterized tumor of this type.

Partial liquid ventilation with perfluorocarbon in the treatment of rats with lethal pneumococcal pneumonia

BACKGROUND

Partial liquid ventilation with perfluorocarbon is a new therapeutic strategy to treat various lung disorders. The current study was undertaken to determine the efficacy of partial liquid ventilation with a perfluorocarbon (FC-77) in the treatment of pneumococcal pneumonia in rats.

METHODS

Male Wistar rats (weight, 275-300 g; n, 75) were infected via direct intratracheal inoculation with ca 10(9) colony-forming units of viable Streptococcus pneumoniae, serotype 3, and 24 h after infection were placed into one of five groups, each containing 15 rats. The groups were (1) no treatment, (2) one intramuscular injection of penicillin G benzathine (200,000 U), (3) partial liquid ventilation with FC-77, (4) partial liquid ventilation with FC-77 and a single intramuscular dose of penicillin G benzathine (200,000 U), and (5) gas ventilation. Animals were observed every 24 h for survival.

RESULTS

All untreated or gas-ventilated animals or animals that received only partial liquid ventilation were dead by 7 days. Those receiving only partial liquid ventilation survived longer than untreated controls, but ultimately all succumbed by day 7. Survival was 40% for penicillin-treated rats compared with controls (P < 0.05) and 80% for animals treated with both partial liquid ventilation and penicillin versus antibiotic alone (P < 0.05).

CONCLUSIONS

These observations suggest that partial liquid ventilation with perfluorocarbon in combination with antibiotic administration may be an effective therapeutic modality in pneumococcal pneumonia.

MR imaging of benign fatty tumors in children: report of four cases and review of the literature

This study correlates the magnetic resonance imaging characteristics with the pathologic findings in rare benign fatty soft tissue tumors in four children. A review of the literature is presented. Two cases of infiltrating lipoma displayed bright signal on both T1- and T2-weighted images, similar to that observed in subcutaneous fat. Histological study revealed extensive muscle infiltration by mature fat, with some areas of total fatty replacement. The case of facial lipomatosis revealed an extensive process of fatty invasion of adjacent soft tissue and osseous deformity by mass effect of the tumor. This lesion was bright on T1- and T2-weighted images. Histopathologic examination showed widespread invasion of squamous mucosa and skeletal muscle. The single case of lipoblastoma involved the presacral region and right buttock. This lesion, although bright on both T1 and T2 weighting, was relatively hypointense to subcutaneous fat on T1. Microscopic examination revealed a well-encapsulated fatty mass made up of cells ranging from lipoblasts to mature lipocytes. In childhood, when fatty lesions are almost always benign, a morphologic characterization by magnetic resonance may be sufficient basis on which to make critical therapeutic judgements.