Benign Mesothelial Cells in transbronchial biopsy specimens: A potential diagnostic pitfall for lung cancer.

Bronchoscopy is a common diagnostic procedure used to identify lung cancer. Specimens acquired through transbronchial biopsy are pivotal in the diagnosis and molecular characterization of this disease. The occurrence of benign mesothelial cells during a transbronchial biopsy (TBB) is relatively rare. Furthermore, these lesions can sometimes be erroneously identified as malignant, potentially resulting in unwarranted or inappropriate treatment for patients with and without lung cancer. In this retrospective analysis, we examined 619 TBB cases at our institute from 2019 to 2021. Benign mesothelial cells were identified via immunohistochemical studies in eight (1.3%) of 619 cases. These cells were classified into three patterns based on their cellular morphology: monolayer, lace, and cobblestone. Recognizing this phenomenon during the procedure is crucial to accurately distinguish benign mesothelial cells from their cancerous counterparts.

Multiple benign notochordal cell tumors in lung with cystic change.

Benign notochordal cell tumor (BNCT) is a benign lesion derived from notochordal cells. Although it is relatively common in intraosseous lesion, pulmonary BNCT is extremely rare. We present a case of 54-year-old male with multiple pulmonary nodules, in which were considered to be metastatic chordomas initially. For 20 months follow-up without any therapy, most of the nodules had no remarkable change but some nodules showed cystic change. We consulted with pathologists specializing in chordoma and the final diagnosis of the nodules was considered as BNCT rather than chordoma. We herein report the case of multiple pulmonary BNCTs with cystic change, comparing with previous reports.

FLCN alteration drives metabolic reprogramming towards nucleotide synthesis and cyst formation in salivary gland.

FLCN is a tumor suppressor gene which controls energy homeostasis through regulation of a variety of metabolic pathways including mitochondrial oxidative metabolism and autophagy. Birt-Hogg-Dubé (BHD) syndrome which is driven by germline alteration of the FLCN gene, predisposes patients to develop kidney cancer, cutaneous fibrofolliculomas, pulmonary cysts and less frequently, salivary gland tumors. Here, we report metabolic roles for FLCN in the salivary gland as well as their clinical relevance. Screening of salivary glands of BHD patients using ultrasonography demonstrated increased cyst formation in the salivary gland. Salivary gland tumors that developed in BHD patients exhibited an upregulated mTOR-S6R pathway as well as increased GPNMB expression, which are characteristics of FLCN-deficient cells. Salivary gland-targeted Flcn knockout mice developed cytoplasmic clear cell formation in ductal cells with increased mitochondrial biogenesis, upregulated mTOR-S6K pathway, upregulated TFE3-GPNMB axis and upregulated lipid metabolism. Proteomic and metabolite analysis using LC/MS and GC/MS revealed that Flcn inactivation in salivary gland triggers metabolic reprogramming towards the pentose phosphate pathway which consequently upregulates nucleotide synthesis and redox regulation, further supporting that Flcn controls metabolic homeostasis in salivary gland. These data uncover important roles for FLCN in salivary gland; metabolic reprogramming under FLCN deficiency might increase nucleotide production which may feed FLCN-deficient salivary gland cells to trigger tumor initiation and progression, providing mechanistic insight into salivary gland tumorigenesis as well as a foundation for development of novel therapeutics for salivary gland tumors.

Rare squamous cell carcinoma arising from a presacral epidermoid cyst: A case report.

INTRODUCTION: Presacral epidermoid cysts are uncommon, usually benign cysts caused by developmental abnormalities in the fetal period. We present a rare case of squamous cell carcinoma arising from a presacral epidermoid cyst. PRESENTATION OF CASE: A 59-year-old woman complained of tenesmus and discomfort in the buttocks. Computed tomography revealed a 50-mm well-defined cystic mass in the presacrum and a 70-mm solid mass extending from the cyst into the rectum, vagina, and left sciatic spine. On T1-weighted magnetic resonance images, the cyst was unilocular and the mass was marginated with low intensity. On T2-weighted images, the mass had high intensity. A malignant presacral developmental cyst was diagnosed, without obvious metastasis. Using abdominal and parasacral approaches, Hartmann's operation was performed with multiorgan resection, including the sacrum, coccyx, left sciatic spine, internal obturator muscle, rectum, and uterine appendage. Histopathology of the excised specimen revealed a squamous cell carcinoma originating from the presacral epidermoid cyst. DISCUSSION: Reports of malignant transformation of epidermoid cysts in the presacral space, as in the present case, are extremely rare. Because of their unusual location and slow growth, epidermoid cysts tend to remain asymptomatic. Because the patient had a malignant tumor with suspected invasion of adjacent organs, combination surgery was selected. CONCLUSION: Although further research is required, presacral epidermoid cysts are extremely rare and may be malignant. Thorough preoperative image evaluation is crucial for complete resection.

Parotid Oncocytoma as a Manifestation of Birt-Hogg-Dubé Syndrome.

Birt-Hogg-Dubé syndrome (BHD) is a rare autosomal dominant disease characterized by skin fibrofolliculomas, pulmonary cysts, spontaneous pneumothoraces, and renal cancers. Oncocytomas are benign epithelial tumors that are also rare. Recently, there have been a few case reports of BHD with a parotid oncocytoma that appears to have a BHD phenotype. Here we document the eighth known case and describe the magnetic resonance imaging features of the parotid oncocytoma, which mimicked Warthin's tumor. Radiologists should be aware of the association between these rare disorders.

CD10 down expression in follicular lymphoma correlates with gastrointestinal lesion involving the stomach and large intestine.

Follicular lymphoma (FL) shows co-expression of B-cell lymphoma 2 (BCL2) and CD10, whereas downexpression of CD10 is occasionally experienced in gastrointestinal (GI) FL with unknown significance. Gastrointestinal FL is a rare variant of FL, and its similarity with mucosa-associated lymphoid tissue lymphoma was reported. We investigated the clinicopathological and genetic features of CD10 downexpressed (CD10down ) GI-FL. The diagnosis of CD10down FL was carried out with a combination of pathological and molecular analyses. The incidence of CD10down GI-FL was shown in 35/172 (20.3%) cases, which was more frequent than nodal FL (3.5%, P < 0.001). The difference was additionally significant between GI-FL and nodal FL when the analysis was confined to primary GI-FL (55.2% vs 3.5%, P < 0.001). Compared to CD10+ GI-FL, CD10down GI-FL significantly involved the stomach or large intestine (P = 0.015), and additionally showed the downexpression of BCL6 (P < 0.001). The follicular dendritic cell meshwork often showed a duodenal pattern in the CD10down group (P = 0.12). Furthermore, a lymphoepithelial lesion was observed in 5/12 (40%) gastric FL cases, which indicated caution in the differentiation of mucosa-associated lymphoid tissue lymphoma. Molecular analyses were undertaken in seven cases of CD10down GI-FL, and an identical clone was found between CD10down follicles and CD10+ BCL2+ neoplastic follicles. In the diagnosis of cases with CD10down BCL2+ follicles, careful examination with molecular studies should be carried out.

A rare case of inflammatory myofibroblastic tumor of the diaphragmatic parietal pleura with dissemination.

Inflammatory myofibroblastic tumor (IMT) is a rare neoplasm that occurs at different sites in the body. Pleural IMT in particular is especially rare. IMTs infrequently tend to have malignancy. We report a rare case of advanced diaphragmatic parietal pleural IMT with dissemination. A 30-year-old woman complained of right upper abdominal pain. Computed tomography showed a large lobulated mass over the right diaphragm, but no disseminated nodules were noted. Intraoperatively, we found the primary tumor arising from the diaphragmatic parietal pleura and a dozen disseminated nodules, and we removed them completely. The histopathological and immunohistochemical diagnosis was IMT.

[Pulmonary non-tuberculous mycobacteriosis complicated with lung cancer].

A 54-year-old man with pulmonary non-tuberculous mycobacteriosis( pulmonary NTM) who had been treated by antituberculous chemotherapy, developed a new nodule of 1.3 cm in size in the segment 1/2 of the right upper lobe. The cavity of 3.5 cm in size in the segment 6 of the right lower lobe from which Mycobacterium intracellulare was bronchoscopically detected, was suspected to be pulmonary NTM lesion. Since lung cancer was highly suspected by radiological examinations, right upper lobectomy and S6 segmentectomy were performed. Pathological diagnosis for the right upper lobe nodule was adenocarcinoma.

BAFF-R is expressed on B-cell lymphomas depending on their origin, and is related to proliferation index of nodal diffuse large B-cell lymphomas.

B-cell activating factor receptor (BAFF-R) is one of three known receptors for BAFF. BAFF-R is required for B-cell maturation and survival. We tried to determine the normal pattern of BAFF-R expression in non-neoplastic and neoplastic B- and T-cells. We used immunohistochemistry to evaluate the expression pattern of BAFF-R in non-neoplastic and neoplastic lymphoid tissues of routinely fixed paraffin-embedded samples, and examined the relationships among BAFF-R and expressions of CD10, bcl-6, MUM-1, and MIB-1. BAFF-R expression was detected on B-cells of the mantle zones, some cells within germinal centers, and scattered cells in the interfollicular areas of reactive lymph nodes. BAFF-R expression was only found in B-cell lymphoma (60/120, positive samples/examined samples), but not in T/NK cell lymphoma (0/10) or Hodgkin lymphoma (0/10). The proportions were as follows : follicular lymphoma (14/16), diffuse large B-cell lymphoma (DLBCL) (27/61), mantle cell lymphoma (4/4), and Burkitt lymphoma (0/4). According to Hans' criteria, DLBCLs were subclassified into germinal center B-cell-like (GCB) and non-germinal center B-cell-like (non-GCB) types. Interestingly, in nodal lymphomas, in the GCB subgroup (n=12), 9 of 12 (75%) were positive for BAFF-R, while 6 of 20 (30%) were positive in the non-GCB subgroup (n=20) (p < 0.05). In addition, expression of BAFF-R related to lower MIB-1 index was associated with GCB-type DLBCL. In conclusion, BAFF-R was only found in some B-cell lymphomas, which was closely associated with the expression pattern in normal counterparts, although BAFF-R expression on follicular lymphoma is different from that on germinal center cells, which is similar to bcl-2. BAFF-R was rather specifically related to low growth activity of GCB-type DLBCL of nodal origin.

Re-classification of pTNM staging for lung cancer: single-institution report at a Japanese comprehensive cancer hospital.

Among the major cancer sites, the lung has the most complicated pTNM description. Reclassification of International Union Against Cancer (UICC)-pTNM grading of 262 lung cancers resected at Shikoku Cancer Center was done using microscopy and audit of pathology reports. Of the 262 lung cancers, 222 were obtained at operation from 1999 to 2004 and 40 additional cases from 2006. Among 666 pTNM components of the former cases, 37 components (31T, 3N, 3M) in 35 cases were revised to different categories. The concordance rate (CR) of the original stage to the reclassified stage was 90% (210/222) in the five-group staging system (5GSS) without subdivisions and 84% (187/222) in the 8GSS with subdivisions such as IA and IB. It decreased in advanced cases. For example, the CR was higher in stage I (97%, 158/163) than in stage II-IV (88%, 51/59) in five-GSS (chi(2) test, P < 0.05). The CR in 8GSS of the additional 40 cases, which were diagnosed after the review of the former 222 cases, was 98% (39/40), indicating that the knowledge gained from the review improved the accuracy significantly (chi(2) test, P < 0.05). It is necessary to assess disparities in the accuracy of pTNM for lung cancer at each institution. This is also true for cancers at other sites.

Analysis of genomic homology of murine gammaherpesvirus (MHV)-72 to MHV-68 and impact of MHV-72 on the survival and tumorigenesis in the MHV-72-infected CB17 scid/scid and CB17+/+ mice.

Murine gammaherpesvirus (MHV)-68-infected mice are well-known as models for Epstein-Barr virus (EBV)-related lymphoproliferative diseases. MHV-72 may be a relative of MHV-68, but any genetic comparison between the two (except for the M7 gene) has never been reported. The genetic compositions of MHV-72 and MHV-68 were compared and the pathology of MHV-72 infection studied in CB-17 severe combined immunodeficiency (scid/scid; SCID) and CB17 wild-type (CB17+/+) mice. The MHV-72 DNA sequence was almost identical to MHV-68 except for approximately 7000 bp corresponding to the MHV-68 M1-M3 genes. Twenty-seven of 30 MHV-72-infected SCID mice (90%) died from generalized infection with intranuclear viral inclusions for approximately 1 month, while MHV-72-infected CB17+/+ mice recovered from acute infection. Long observation and pathological study of 68 MHV-72-infected mice for up to 24 months revealed that the survival rate (29.4%) and survival time (21.3 months) of MHV-72-infected CB17+/+ mice were significantly lower (P = 0.0127) and shorter (P = 0.0065) than those of the controls (61.1% and 22.9 months), respectively. The malignancy development rate (60.3%) of the infected CB17+/+ mice was also significantly higher (P = 0.004) than those of the controls (22.2%). However, no MHV-72 DNA was detected in the tumors of infected mice. MHV-72 may have some tumor-promoting effects but the tumorigenesis in infected CB17+/+ mice is different from EBV-associated tumors.

Ileal ulcers and cytomegalovirus infection in a case of Churg-Strauss syndrome.

Churg-Strauss syndrome, or allergic granulomatous angiitis, is an uncommon vasculitic syndrome. We describe a 53-year-old man with Churg-Strauss syndrome and subsequent opportunistic cytomegalovirus enterocolitis. During intensive care, including steroid-pulse therapy, the patient developed rapidly progressive anemia caused by active bleeding from his small intestine, resulting in resection of 20 cm of ileum. Diagnosis of Churg-Strauss syndrome was confirmed both by characteristic clinical features and by histology. Histologic examination also revealed multiple shallow ulcers accompanied by cytomegalovirus infection. Characteristic angiitis was found in the ileum with normal-like mucosa, and it was not necessarily associated with ileal ulcers. This finding suggests that cytomegalovirus infection may be one of the causes or exacerbating factors for ileal ulcers in Churg-Strauss syndrome, although ulcers of the intestine have usually been considered to be caused by ischemia resulting from angiitis.