Yoshito Hoshika

Quantitative CT analysis of small pulmonary vessels in lymphangioleiomyomatosis

BACKGROUNDS Lymphangioleiomyomatosis (LAM) is a destructive lung disease that share clinical, physiologic, and radiologic features with chronic obstructive pulmonary disease (COPD). This study aims to identify those features that are unique to LAM by using quantitative CT analysis. METHODS We measured total cross-sectional areas of small pulmonary vessels (CSA) less than 5mm(2) and 5-10mm(2) and calculated percentages of those lung areas (%CSA), respectively, in 50 LAM and 42 COPD patients. The extent of cystic destruction (LAA%) and mean parenchymal CT value were also calculated and correlated with pulmonary function. RESULTS The diffusing capacity for carbon monoxide/alveolar volume (DL(CO)/VA %predicted) was similar for both groups (LAM, 44.4 ± 19.8% vs. COPD, 45.7 ± 16.0%, p=0.763), but less tissue damage occurred in LAM than COPD (LAA% 21.7 ± 16.3% vs. 29.3 ± 17.0; p<0.05). Pulmonary function correlated negatively with LAA% (p<0.001) in both groups, yet the correlation with %CSA was significant only in COPD (p<0.001). When the same analysis was conducted in two groups with equal levels of LAA% and DL(CO)/VA %predicted, %CSA and mean parenchymal CT value were still greater for LAM than COPD (p<0.05). CONCLUSIONS Quantitative CT analysis revealing a correlation between cystic destruction and CSA in COPD but not LAM indicates that this approach successfully reflects different mechanisms governing the two pathologic courses. Such determinations of small pulmonary vessel density may serve to differentiate LAM from COPD even in patients with severe lung destruction.

Prevalence and clinical features of lymphedema in patients with lymphangioleiomyomatosis.

BACKGROUND Lymphangioleiomyomatosis (LAM) is a rare cystic lung disease predominantly affecting young women. Some of these patients develop lymphedema of the lower extremities and buttocks; however, neither the exact frequency of LAM-associated lymphedema nor the clinical features of such patients is well delineated. OBJECTIVES To document the frequency, features, and treatment of LAM-associated lymphedema. METHODS We reviewed all medical records of patients listed in the Juntendo University LAM registry for the 30 years preceding August 2010. RESULTS Of 228 patients registered with a diagnosis of LAM, eight (3.5%) had LAM-associated lymphedema of the lower extremities. All were females with sporadic LAM, and their mean age when diagnosed was 32.5 years (range 23-44). Lymphedema of the lower extremities was the chief or a prominent presenting feature in five of these LAM patients. CT scans showed that all eight patients had enlarged lymph nodes (lymphangioleiomyomas) in the retroperitoneum and/or pelvic cavity. Yet, cystic destruction of the lungs was mild in four patients, moderate in two and severe only in two. Seven of these patients were treated by administering a fat-restricted diet and complex decongestive physiotherapy, and four received a gonadotropin-releasing hormone analog. With this combined protocol, all eight patients benefitted from complete relief or good control of the lymphedema. CONCLUSIONS Lymphedema is a rare complication of LAM and may be associated with axial lymphatic involvement or dysfunction rather than severe cystic lung destruction. The combined multimodal treatments used here effectively resolved or controlled LAM-associated lymphedema.

Benign clear cell “sugar” tumor of the lung in a patient with Birt-Hogg-Dubé syndrome: a case report

BackgroundBirt-Hogg-Dubé (BHD) syndrome is a rare inherited autosomal genodermatosis and caused by germline mutation of the folliculin (FLCN) gene, a tumor suppressor gene of which protein product is involved in mechanistic target of rapamycin (mTOR) signaling pathway regulating cell growth and metabolism. Clinical manifestations in BHD syndrome is characterized by fibrofolliculomas of the skin, pulmonary cysts with or without spontaneous pneumothorax, and renal neoplasms. There has been no pulmonary neoplasm reported in BHD syndrome, although the condition is due to deleterious sequence variants in a tumor suppressor gene. Here we report, for the first time to our knowledge, a patient with BHD syndrome who was complicated with a clear cell “sugar” tumor (CCST) of the lung, a benign tumor belonging to perivascular epithelioid cell tumors (PEComas) with frequent causative relation to tuberous sclerosis complex 1 (TSC1) or 2 (TSC2) gene.Case presentationIn a 38-year-old Asian woman, two well-circumscribed nodules in the left lung and multiple thin-walled, irregularly shaped cysts on the basal and medial area of the lungs were disclosed by chest roentgenogram and computer-assisted tomography (CT) during a preoperative survey for a bilateral faucial tonsillectomy. Analysis of the resected tumor showed large polygonal cells with clear cytoplasm proliferating in a solid pattern. Immunohistochemistry revealed that these tumor cells were positive for microphthalmia-transcription factor, S100, and CD1a but negative for HMB45, indicating that the tumor was a CCST. Genetic testing indicated that the patient had a germline mutation on exon 12 of the FLCN gene, i.e., insertion of 7 nucleotides (CCACCCT) (c.1347_1353dupCCACCCT). Direct sequencing of the FLCN exon 12 using genomic DNA obtained from her microdissected CCST cells clearly revealed loss of the wild-type FLCN sequence, which confirmed complete functional loss of the FLCN gene. On the other hand, no loss of heterozygosity around TCS1- or TSC2-associated genetic region was demonstrated.ConclusionTo our knowledge, this is the first report of CCST of the lung in a patient with BHDS, indicating that CCST should be added to the spectrum of pulmonary manifestations of BHDS.

Isolation of Individual Cellular Components from Lung Tissues of Patients with Lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare neoplastic disease entailing cystic destruction of the lungs and progressive respiratory failure. LAM lungs are histologically characterized by the proliferation of smooth muscle-like cells (LAM cells) and an abundance of lymphatic vessels. To elucidate the pathophysiological processes of LAM, cell-type-specific analyses are required. However, no method exists for isolating the individual types of cells in LAM lesions. Therefore, we established a fluorescence-activated cell sorting (FACS)-based method for the direct isolation of LAM cells and other various cellular components from LAM-affected lung tissue. We obtained LAM-affected lung tissue from resections or transplant recipients and prepared single-cell suspensions. FACS, immunohistochemical, and molecular analysis were used cooperatively to isolate HMB45-positive LAM cells with tuberous sclerosis complex (TSC) 2 loss of heterozygosity (LOH). Using a combination of antibodies against an epithelial cell adhesion molecule (EpCAM) and podoplanin, we fractionated CD45-negative lung cells into three groups: lymphatic endothelial cells (LEC) (EpCAM(-)/podoplanin(hi) subset), alveolar type II cells (EpCAM(hi)/podoplanin(-) subset), and mesenchymal cells (EpCAM(-)/podoplanin(-/low) subset). During subsequent analysis of HMB45 expression, as a LAM-specific marker, we clearly identified LAM cells in the mesenchymal cell population. We then discovered that CD90(+)/CD34(-) cells in the mesenchymal cell population are not only positive for HBM45 but also had TSC2 LOH. These isolated cells were viable and subsequently amenable to cell culture. This method enables us to isolate LAM cells and other cellular components, including LAM-associated LEC, from LAM-affected lung tissues, providing new research opportunities in this field.