Detection of low-prevalence somatic TSC2 mutations in sporadic pulmonary lymphangioleiomyomatosis tissues by deep sequencing.

Lymphangioleiomyomatosis (LAM) (MIM #606690) is a rare lung disorder leading to respiratory failure associated with progressive cystic destruction due to the proliferation and infiltration of abnormal smooth muscle-like cells (LAM cells). LAM can occur alone (sporadic LAM, S-LAM) or combined with tuberous sclerosis complex (TSC-LAM). TSC is caused by a germline heterozygous mutation in either TSC1 or TSC2, and TSC-LAM is thought to occur as a result of a somatic mutation (second hit) in addition to a germline mutation in TSC1 or TSC2 (first hit). S-LAM is also thought to occur under the two-hit model involving a somatic mutation and/or loss of heterozygosity in TSC2. To identify TSC1 or TSC2 changes in S-LAM patients, the two genes were analyzed by deep next-generation sequencing (NGS) using genomic DNA from blood leukocytes (n = 9), LAM tissue from lung (n = 7), LAM cultured cells (n = 4), or LAM cell clusters (n = 1). We identified nine somatic mutations in six of nine S-LAM patients (67 %) with mutant allele frequencies of 1.7-46.2 %. Three of these six patients (50 %) showed two different TSC2 mutations with allele frequencies of 1.7-28.7 %. Furthermore, at least five mutations with low prevalence (<20 % of allele frequency) were confirmed by droplet digital PCR. As LAM tissues are likely to be composed of heterogeneous cell populations, mutant allele frequencies can be low. Our results confirm the consistent finding of TSC2 mutations in LAM samples, and highlight the benefit of laser capture microdissection and in-depth allele analyses for detection, such as NGS.

Multisystem Langerhans cell histiocytosis in an adult non-smoker treated with steroid therapy.

We describe the case of a 29-year-old female non-smoker who was treated with steroid therapy for a subacute exacerbation of multisystem Langerhans cell histiocytosis (MS-LCH) with worsening lung, skin, and oral mucosal lesions. The patient developed pneumonia, and computed tomography (CT) showed multiple thin-walled cavities. Transbronchial lung cryobiopsy (TBLC) specimens revealed Langerhans cells, which were positive for CD1a and S-100 expression. Similar histological findings were detected in the submandibular gland, skin, and tooth. On the basis of these findings, the patient was diagnosed with MS-LCH and subsequently treated with steroid therapy. From the literature review, case reports of non-smokers with pulmonary lesions that worsened and required treatment are rare. Almost all cases recurred and needed additional treatment. This case study contributes to our understanding of the potential role of steroid therapy in MS-LCH treatment. Additionally, TBLC is a novel, potentially safer, diagnostic tool that has not been previously described for LCH.

[A case of slowly progressive intravascular lymphoma with respiratory failure caused by diffuse pulmonary vasoconstriction].

A 71-year-old man developed intermittent fever with high serum lactate dehydrogenase in December 2006. Although persistent high grade fever and hypoxia appeared in July 2007, chest and abdominal CT showed no abnormal findings. On admission to our hospital in September 2007, chest CT demonstrated multiple micro-nodules in both lungs. Since diffuse lung capacity was extremely low and lung perfusion decreased diffusely, we performed video-associated lung biopsy and intravascular lymphoma was diagnosed. Histological examination of the lung specimen revealed a small number of atypical lymphocytes and some thrombi in capillaries. These findings suggested that severe hypoxia was caused mainly by diffuse pulmonary vasoconstriction due to some small thrombi and tumor cells, not by their embolization. Hypoxia improved dramatically in a few days after initiation of chemotherapy including rituximab.

Erdheim-Chester disease progression from miliary pulmonary nodules to large tumours.

Erdheim-Chester disease (ECD), a rare form of non-Langerhans cell histiocytosis, affects long bones, the retroperitoneal region, and the central nervous, cardiovascular, and pulmonary systems. Most patients with ECD show interlobular septal thickening, centrilobular micronodules, and ground glass opacities on chest computed tomography (CT). We encountered a 66-year-old man with ECD who presented at first visit with randomly distributed multiple pulmonary nodules and who then developed large tumour shadows, observed on chest CT. To our knowledge, this random distribution pattern of multiple pulmonary nodules has not previously been reported.

Correlation between FDG-PET findings and GLUT1 expression in salivary gland pleomorphic adenomas.

OBJECTIVE: One reason for the difficulty in accurate preoperative pathological diagnosis of major salivary gland tumors with fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) is the tendency of pleomorphic adenomas to have a high, standardized uptake value (SUV). The expression of glucose transporter 1 (GLUT1) and the quantity of GLUT1 messenger RNA (mRNA) were analyzed in specimens of pleomorphic adenoma to identify whether GLUT1 is responsible for the increased glucose uptake in FDG-PET examinations of these tumors. METHODS: Eighty salivary gland tumors resected at Yokohama City University Hospital were retrospectively investigated. FDG-PET was performed prior to surgery. PET images were evaluated by two experienced radiologists. GLUT1 was immunohistochemically stained, and GLUT1 mRNA density was quantified using real-time polymerase chain reaction in 10 of 40 pleomorphic adenomas. RESULTS: The pleomorphic adenomas stained positively for GLUT1, and there was significant correlation between the GLUT1 index and the SUV in FDG-PET. CONCLUSIONS: GLUT1 is expressed in salivary gland pleomorphic adenomas. Furthermore, the GLUT1 index shows significant correlation with the SUV of FDGPET. This result suggests that GLUT1 plays an important role in increasing FDG uptake in salivary gland pleomorphic adenomas.

The importance of subpleural fibrosis in the prognosis of patients with idiopathic interstitial pneumonias.

PURPOSE: To compare computer-aided diagnostic results with histological findings obtained by surgical biopsy and evaluate whether subpleural lesion volumes can aid identification of idiopathic pulmonary fibrosis (IPF). MATERIALS AND METHODS: We retrospectively analyzed computed tomography (CT) images of 79 patients (43 with fibrosing nonspecific interstitial pneumonia (fNSIP) and 36 with IPF) using the Gaussian Histogram Normalized Correlation (GHNC) system. We determined the H-pattern based on honeycomb and/or fibrosis with traction bronchiectasis on CT, and measured the H-pattern volume ratio at the biopsy sites and in the subpleural area. The biopsy site CT data were compared with biopsy specimens using Spearman's correlation. H-pattern volumes in the subpleural area within 2mm under the pleura (H2) were analyzed to predict IPF diagnosis and patients prognosis. RESULTS: The H-pattern volume ratio at the biopsy sites showed significant correlation with histological honeycomb (r=0.355, p<0.001), subpleural collapse (r=0.410, p<0.001), and heterogeneity (r=0.484, p<0.001). Multivariate regression analysis, adjusting for age, sex, and CT results, revealed that the H2 was a significant independent predictor of IPF diagnosis (odds ratio: 1.073; p=0.048). H2 correlated with patients' survival after adjusting for age (p=0.003). CONCLUSION: The computer-aided H-pattern volume ratio of the subpleural area indicates subpleural abnormalities quantitatively and may help diagnose IPF.

Late cardiac metastasis from colorectal carcinoma 15 years after surgery.

Late recurrence of malignant tumors in the heart more than 10 years after surgery is quite rare, especially for colorectal carcinoma. Here, we report a case of late cardiac metastasis from a primary colorectal carcinoma, which occurred more than 15 years after the initial surgery. To our knowledge, this is the first such reported case.