Thoracic nuclear protein in testis (NUT) carcinoma: expanded pathological spectrum with expression of thyroid transcription factor-1 and neuroendocrine markers.

AIMS: Nuclear protein in testis (NUT) carcinoma, an aggressive tumour driven by NUTM1 rearrangements, often involves the lung/mediastinum and shows squamous differentiation. We encountered an index patient with a thoracic NUT carcinoma diagnosed by molecular testing, showing extensive pleural involvement and diffuse thyroid transcription factor-1 (TTF-1) expression, initially suggestive of lung adenocarcinoma with pseudomesotheliomatous growth. We thus gathered an institutional series of thoracic NUT carcinomas to examine their pathological spectrum. METHODS AND RESULTS: We searched for thoracic NUT carcinomas in our surgical pathology files and in 2289 consecutive patients with primary thoracic tumours investigated with RNA-based assays. We performed NUT immunohistochemistry on 425 additional lung adenocarcinomas. Collectively, we identified six patients (five men and one woman; age 31-80 years; four never-smokers) with thoracic NUT carcinomas confirmed by molecular testing (including five with positive NUT immunohistochemistry). They died at 2.3-12.9 months (median, 2.8 months) after presentation. Two patients were diagnosed by histopathological assessment, and the remaining four (including the index patient) were diagnosed by molecular testing. Analysis of the index case revealed expression of multiple neuroendocrine markers and TTF-1; no ultrastructural evidence of neuroendocrine differentiation was noted. No additional NUT-positive cases were found by immunohistochemical screening. CONCLUSIONS: Although NUT carcinoma classically shows squamous differentiation, it can rarely express TTF-1 (even diffusely) and/or multiple neuroendocrine markers. This immunophenotypic spectrum may lead to diagnostic confusion with pulmonary adenocarcinoma, neuroendocrine tumour, and others. To circumvent this pitfall, NUT immunohistochemistry and/or NUTM1 molecular testing should be considered in primitive-appearing tumours, regardless of their immunophenotypic features.

Malignant mesothelioma following repeated exposures to cosmetic talc: A case series of 75 patients.

BACKGROUND: Asbestos is the primary known cause of malignant mesothelioma. Some cosmetic talc products have been shown to contain asbestos. Recently, repeated exposures to cosmetic talc have been implicated as a cause of mesothelioma. METHODS: Seventy-five individuals (64 females; 11 males) with malignant mesothelioma, whose only known exposure to asbestos was repeated exposures to cosmetic talcum powders, were reviewed in medical-legal consultation. Out of the 75 cases, 11 were examined for asbestiform fibers. RESULTS: All subjects had pathologically confirmed malignant mesothelioma. The mean age at diagnosis was 61 ± 17 years. The mean latency from exposure to diagnosis was 50 ± 13 years. The mean exposure duration was 33 ± 16 years. Four mesotheliomas (5%) occurred in individuals working as barbers/cosmetologists, or in a family member who swept the barber shop. Twelve (16%) occurred in individuals less than 45 years old (10 females; 2 males). Forty-eight mesotheliomas were pleural (40 females; 8 males), 23 were peritoneal (21 females; 2 males). Two presented with concomitant pleural and peritoneal disease. There was one pericardial, and one testicular mesothelioma. The majority (51) were of the epithelioid histological subtype, followed by 13 biphasic, 8 sarcomatoid, 2 lymphohistiocytoid, and 1 poorly differentiated. Of the 11 individuals whose nontumorous tissues were analyzed for the presence of asbestiform fibers, all showed the presence of anthophyllite and/or tremolite asbestos. CONCLUSIONS: Mesotheliomas can develop following exposures to cosmetic talcum powders. These appear to be attributable to the presence of anthophyllite and tremolite contaminants in cosmetic talcum powder.

A Conserved Distal Lung Regenerative Pathway in Acute Lung Injury.

Improved tools have led to a burgeoning understanding of lung regeneration in mice, but it is not yet known how these insights may be relevant to acute lung injury in humans. We report in detail two cases of fulminant idiopathic acute lung injury requiring extracorporeal membrane oxygenation in previously healthy young adults with acute respiratory distress syndrome, one of whom required lung transplantation. Biopsy specimens showed diffuse alveolar injury with a striking paucity of alveolar epithelial regeneration, rare hyaline membranes, and diffuse contiguous airspace lining by macrophages. This novel constellation was termed diffuse alveolar injury with delayed epithelization. In addition, mirroring data from murine models of lung injury/regeneration, peribronchiolar basaloid pods (previously described as squamous metaplasia) and ciliated bronchiolarization were identified in these patients and in 39% of 57 historical cases with diffuse alveolar damage. These findings demonstrate a common and clinically relevant human disease correlate for murine models of severe acute lung injury. Evidence suggests that peribronchiolar basaloid pods and bronchiolarization are related spatially and temporally and likely represent overlapping sequential stages of the response to severe distal airway injury.

Malignant mesothelioma in Lynch syndrome: A report of two cases and a review of the literature.

Malignant mesothelioma is a rare and aggressive cancer most typically associated with prior asbestos exposure. The nature of the relationship between asbestos exposure and hereditary familial syndromes predisposing to malignancy has not been determined. We report two Lynch syndrome patients with paraoccupational asbestos exposure who developed diffuse malignant mesothelioma of the pleura or peritoneum. Interestingly, one showed a separate focus of pleural well-differentiated papillary mesothelioma. It is likely that Lynch syndrome patients are at increased risk for the development of mesothelioma in the setting of exposure to asbestos, even at what is generally considered to be low levels. In the presence of a documented history of low-level asbestos exposure, patients with genetic predisposition disorders (including Lynch syndrome) should be considered to have an independent risk factor modifying the effects of asbestos exposure.

Multiple calcifying fibrous pseudotumors of the pleura: ultrastructural analysis provides insight on mechanism of dissemination.

Calcifying fibrous pseudotumor (CFP) is a rare, benign soft tissue tumor that may uncommonly arise in the pleura. These tumors can show multifocal dissemination across the pleural surface, but the mechanism underlying this dissemination is unclear. Review of previously reported cases of pleural CFP demonstrates a strong predilection for basal and diaphragmatic pleural surfaces, and a significantly higher rate of multifocality compared with other locations. We present a 59-year-old male with multiple CFP of the pleura. Reactive-appearing adhesions spanning the pleural surfaces were present, and by electron microscopy, were involved by tumor. We suggest this is the likely mode of dissemination across the pleural surfaces.

Pulmonary adenocarcinoma with epidermal growth factor receptor-mutations in asbestos exposed non-smokers: A case series.

BACKGROUND: Cigarette smoke and asbestos are recognized causes of lung carcinoma and together promote carcinogenesis. Adenocarcinoma is currently the most common cause of lung cancer in the USA and it has been linked to both smoking and asbestos exposure. Mutations in the epidermal growth factor gene receptor (EGFR) occur predominantly in non-smokers with adenocarcinoma. Methods Mutations in the EGFR gene were investigated using next-generation sequencing. RESULTS: We report the presence of EGFR exon point mutations in the pulmonary adenocarcinomas of three never-smokers occupationally exposed to asbestos. CONCLUSION: The role of asbestos as a possible cause of EGFR mutagenesis requires further investigation. Am. J. Ind. Med. 60:306-309, 2017. © 2017 Wiley Periodicals, Inc.

Diffuse peritoneal mesothelioma: A case series of 62 patients including paraoccupational exposures to chrysotile asbestos.

BACKGROUND: Diffuse peritoneal malignant mesothelioma (DPM) is caused by exposure to asbestos. The medical literature has linked DPM primarily to high levels of asbestos exposure, in particular amosite. Controversy persists as to whether chrysotile is capable of causing DPM, especially when exposures are paraoccupational. METHODS: Sixty-two subjects (51 men, 11 women) with DPM were reviewed in medical-legal consultation with deposition and product identification evidence. RESULTS: All had pathologically confirmed DPM. Most were exposed to both amphibole and chrysotile, but chrysotile alone was documented in 14/62 (26%) cases. A total of 7/14 (50%) cases of the paraoccupational exposures were to chrysotile alone. Women were younger than men as were those with paraoccupational versus those with occupational exposure. The mean duration of exposure for all cases was 17.9 ± 10 years and latency from time of first exposure was 45.9 + 11.6 years. CONCLUSIONS: DPM occurs with both occupational and paraoccupational exposures to asbestos and may be seen in paraoccupational exposures to chrysotile asbestos.

Lung [(18)F]fluorodeoxyglucose uptake and ventilation-perfusion mismatch in the early stage of experimental acute smoke inhalation.

BACKGROUND: Acute lung injury occurs in a third of patients with smoke inhalation injury. Its clinical manifestations usually do not appear until 48-72 h after inhalation. Identifying inflammatory changes that occur in pulmonary parenchyma earlier than that could provide insight into the pathogenesis of smoke-induced acute lung injury. Furthermore, noninvasive measurement of such changes might lead to earlier diagnosis and treatment. Because glucose is the main source of energy for pulmonary inflammatory cells, the authors hypothesized that its pulmonary metabolism is increased shortly after smoke inhalation, when classic manifestations of acute lung injury are not yet expected. METHODS: In five sheep, the authors induced unilateral injury with 48 breaths of cotton smoke while the contralateral lung served as control. The authors used positron emission tomography with: (1) [F]fluorodeoxyglucose to measure metabolic activity of pulmonary inflammatory cells; and (2) [N]nitrogen in saline to measure shunt and ventilation-perfusion distributions separately in the smoke-exposed and control lungs. RESULTS: The pulmonary [F]fluorodeoxyglucose uptake rate was increased at 4 h after smoke inhalation (mean ± SD: 0.0031 ± 0.0013 vs. 0.0026 ± 0.0010 min; P < 0.05) mainly as a result of increased glucose phosphorylation. At this stage, there was no worsening in lung aeration or shunt. However, there was a shift of perfusion toward units with lower ventilation-to-perfusion ratio (mean ratio ± SD: 0.82 ± 0.10 vs. 1.12 ± 0.02; P < 0.05) and increased heterogeneity of the ventilation-perfusion distribution (mean ± SD: 0.21 ± 0.07 vs. 0.13 ± 0.01; P < 0 .05). CONCLUSION: Using noninvasive imaging, the authors demonstrated that increased pulmonary [F]fluorodeoxyglucose uptake and ventilation-perfusion mismatch occur early after smoke inhalation.

Potential of 18F-FDG PET toward personalized radiotherapy or chemoradiotherapy in lung cancer.

PURPOSE: We investigated the metabolic response of lung cancer to radiotherapy or chemoradiotherapy by (18)F-FDG PET and its utility in guiding timely supplementary therapy. METHODS: Glucose metabolic rate (MRglc) was measured in primary lung cancers during the 3 weeks before, and 10-12 days (S2), 3 months (S3), 6 months (S4), and 12 months (S5) after radiotherapy or chemoradiotherapy. The association between the lowest residual MRglc representing the maximum metabolic response (MRglc-MMR) and tumor control probability (TCP) at 12 months was modeled using logistic regression. RESULTS: We accrued 106 patients, of whom 61 completed the serial (18)F-FDG PET scans. The median values of MRglc at S2, S3 and S4 determined using a simplified kinetic method (SKM) were, respectively, 0.05, 0.06 and 0.07 µmol/min/g for tumors with local control and 0.12, 0.16 and 0.19 µmol/min/g for tumors with local failure, and the maximum standard uptake values (SUVmax) were 1.16, 1.33 and 1.45 for tumors with local control and 2.74, 2.74 and 4.07 for tumors with local failure (p < 0.0001). MRglc-MMR was realized at S2 (MRglc-S2) and the values corresponding to TCP 95 %, 90 % and 50 % were 0.036, 0.050 and 0.134 µmol/min/g using the SKM and 0.70, 0.91 and 1.95 using SUVmax, respectively. Probability cut-off values were generated for a given level of MRglc-S2 based on its predicted TCP, sensitivity and specificity, and MRglc ≤0.071 µmol/min/g and SUVmax ≤1.45 were determined as the optimum cut-off values for predicted TCP 80 %, sensitivity 100 % and specificity 63 %. CONCLUSION: The cut-off values (MRglc ≤0.071 µmol/min/g using the SKM and SUVmax ≤1.45) need to be tested for their utility in identifying patients with a high risk of residual cancer after standard dose radiotherapy or chemoradiotherapy and in guiding a timely supplementary dose of radiation or other means of salvage therapy.

Postradiofrequency ablation inflammatory pseudotumor associated with pulmonary venoocclusive disease: case report and review of the literature.

Radiofrequency ablation of pulmonary veins is a common therapeutic intervention for atrial fibrillation. Pulmonary vein stenosis and venoocclusive disease are recognized complications, but the spectrum of pathologies postablation have not been previously reviewed. A recent case at our hospital showed a left hilar soft tissue mass in association with superior pulmonary vein stenosis in a patient 4 years postablation. On resection, this proved to be an inflammatory pseudotumor composed of myofibroblasts in an organizing pneumonia-type pattern with adjacent dendriform ossifications. Pulmonary venoocclusive change was a prominent feature. Literature on the histopathology of postradiofrequency ablation complications is limited. The severity of vascular pathology appears to increase with the postablation interval. Although pulmonary vascular changes are the most common late finding, fibroinflammatory changes including pulmonary pseudotumor formation, attributable to thermal injury, should be considered in the differential diagnosis of these cases.

Malacoplakia of the tongue complicating the site of irradiation for squamous cell carcinoma with review of the literature.

Malacoplakia is a benign and uncommon inflammatory response that develops most frequently in the genitourinary tract but has been reported at other sites. We report the case of 67-year-old man who presented with a lesion at the base of the tongue 7 months after chemoradiation for biopsy-proven invasive squamous cell carcinoma of the tongue. The lesion showed intense avidity by positron emission tomography and was biopsied with the putative clinical diagnosis of recurrent malignancy. Histologically, the lesion showed the characteristics of malacoplakia as well as abundant intracellular gram-negative bacilli. Ultrastructural analysis revealed giant lysosomes, intracytoplasmic calcific concretions (Michaelis-Gutman bodies), and partially digested gram-negative bacilli within vacuolated lysosomes of macrophages. To our knowledge, this is the seventh reported case of malacoplakia of the tongue and the first to develop at the site of prior radiation treatment of a carcinoma. The clinical features of this case, a review of previously reported cases, and a consideration of pathogenesis are presented.