Metanephric adenoma is a rare renal epithelial tumor. Its light microscopic features are very characteristic, and immunohistochemical and electron microscopic studies are not critical to the diagnosis. The literature indicate that, to date, the tumor has behaved in a benign fashion, and predominantly but not exclusively occurred in middle-aged women. It occurs in a wide range up to 11 cm and is usually an incidental finding but may be symptomatic with hematuria or flank pain. Recently, we have experienced a case of renal tumor showing distinctive adenomatous features, which is incidentally found in a 52-year-old female. This tumor is confined to the renal cortex and is well-circumscribed with a characteristic uniform and orderly proliferation of compact well-differentiated small tubules lined by bland oval cells with a very low level of mitotic activity. The term metanephric adenoma is appropriate for this tumor because it accurately describes its bland proliferation of tubules and reflects the embryonic architectural and cytological appearance of this proliferation. The pattern of the tumor, with its occasional papillary glomeruloid- like bodies and foci of elongated tubules, is reminiscent of the fetal metanephric kidney.
Adenoma* ; Diagnosis ; Female ; Flank Pain ; Hematuria ; Humans ; Incidental Findings ; Kidney* ; Middle Aged

Perineurial cells, which normally surround the nerve fascicles within a nerve, can be distinguished from Schwann cells by their immunoreactivity for epithelial membrane antigen (EMA) and lack of reactivity for S-100 protein. Perineurioma is a form of benign peripheral nerve sheath tumor (PNST) almost exclusively composed of perineurial cells. It is often difficult to differentiate this tumor from the other benign PNSTs or ectopic meningioma by histology alone. Immunohistochemical and electron microscopic studies are helpful for differential diagnosis. We recently experienced a case of soft tissue perineurioma in a 14-year-old girl. This tumor was presented as a 5.6 cm sized subcutaneous movable mass in the elbow. The well encapsulated soft tissue tumor consisted of spindle cells which have whorling and storiform patterns within the collagenous stroma. The spindle cells were stained positive for EMA but negative for S-100 protein, chromogranin, neuron-specific enolase or Leu-7. Ultrastructurally, they possessed long cytoplasmic processes with incomplete basal lamina, primitive intercellular junction and occasional pinocytotic vesicles.
Adolescent ; Basement Membrane ; Collagen ; Cytoplasm ; Diagnosis, Differential ; Elbow ; Female ; Humans ; Immunohistochemistry ; Intercellular Junctions ; Meningioma ; Microscopy, Electron ; Mucin-1 ; Nerve Sheath Neoplasms* ; Peripheral Nerves ; Phosphopyruvate Hydratase ; S100 Proteins ; Schwann Cells

BACKGROUND: Dermatofibroma (DF) comprises a heterogeneous group of mesenchymal tumors, with fibroblastic and histiocytic elements present in varying proportions. The cell of origin of DF has been investigated, but remains unclear. OBJECTIVE: The present study attempted to investigate the expression of leukocyte-specific protein 1 (LSP1), a marker of fibrocytes, in DF. Additionally, we evaluated the effectiveness of LSP1 in the differential diagnosis of DF from dermatofibrosarcoma protuberans (DFSP). METHODS: Immunohistochemical staining was performed on 20 cases of DF using antibodies against LSP1, CD68, and factor XIIIa (FXIIIa). In addition, the expression of LSP1 and FXIIIa was evaluated in 20 cases of DFSP. RESULTS: Eighteen of 20 cases (90%) of DF stained positive for LSP1, with variation in the intensity of expression. CD68 was positive in 10 cases (50%), and FXIIIa was expressed in all cases of DF. There were differences between the regional expression patterns of the three markers in individual tumors. In contrast, only 2 of 20 cases of DFSP expressed LSP1, and none of DFSP cases stained positive for FXIIIa. CONCLUSION: The LSP1-positive cells in DF could potentially be fibrocyte-like cells. FXIIIa and CD68 expression suggests that dermal dendritic cells and histiocytes are constituent cells of DF. It is known that fibrocytes, dermal dendritic cells and histiocytes are all derived from CD14+ monocytes. Therefore, we suggest that DF may originate from CD14+ monocytes. Additionally, the LSP1 immunohistochemical stain could be useful in distinguishing between DF and DFSP.
Antibodies ; Dermatofibrosarcoma ; Diagnosis* ; Diagnosis, Differential ; Factor XIIIa ; Fibroblasts ; Histiocytes ; Histiocytoma, Benign Fibrous* ; Langerhans Cells ; Monocytes

BACKGROUND: Assessment of programmed cell death-ligand 1 (PD-L1) immunohistochemical staining is used for treatment decisions in non-small cell lung cancer (NSCLC) regarding use of PD-L1/programmed cell death protein 1 (PD-1) immunotherapy. The reliability of the PD-L1 22C3 pharmDx assay is critical in guiding clinical practice. The Cardiopulmonary Pathology Study Group of the Korean Society of Pathologists investigated the interobserver reproducibility of PD-L1 staining with 22C3 pharmDx in NSCLC samples.METHODS: Twenty-seven pathologists individually assessed the tumor proportion score (TPS) for 107 NSCLC samples. Each case was divided into three levels based on TPS: <1%, 1%–49%, and ≥50%.RESULTS: The intraclass correlation coefficient for TPS was 0.902±0.058. Weighted κ coefficient for 3-step assessment was 0.748±0.093. The κ coefficients for 1% and 50% cut-offs were 0.633 and 0.834, respectively. There was a significant association between interobserver reproducibility and experience (formal PD-L1 training, more experience for PD-L1 assessment, and longer practice duration on surgical pathology), histologic subtype, and specimen type.CONCLUSIONS: Our results indicate that PD-L1 immunohistochemical staining provides a reproducible basis for decisions on anti–PD-1 therapy in NSCLC.
Carcinoma, Non-Small-Cell Lung ; Cell Death ; Immunohistochemistry ; Immunotherapy ; Observer Variation ; Pathology

The significant advance in the development of molecular-targeting drugs has made an evaluation of Her-2, EGFR, and cyclin D1 an important clinical issue in breast cancer patients. This study compared the Her-2, EGFR, and cyclin D1 status of primary tumors as well as their matching lymph node metastases using immunohistochemistry (IHC) and chromogenic in situ hybridization (CISH) in 73 breast cancer patients. Her-2, EGFR, and cyclin D1 protein showed a concordance between the primary lesion and the metastatic regional lymph nodes in 82%, 90%, and 63%, respectively. CISH also revealed 92%, 93%, and 85% concordance in the gene amplification status of Her-2, EGFR, and cyclin D1, showing a reasonable agreement between primary tumors and metastatic regional lymph nodes. Although a statistically significant agreement was found in Her-2 expression, a relatively high discordance rate (18%) raises a little concern. Our findings suggest that the Her-2 status can be reliably assessed on primary tumor but a possible difference can be found in Her-2, EGFR, and cyclin D1 status between the primary and the metastatic sites and this possibility should be concerned in patients considering molecular targeted therapy or patients with progress of disease.
Adult ; Aged ; Breast Neoplasms/genetics/*metabolism/pathology ; Chromogenic Compounds ; Cyclin D1/*analysis/genetics ; Female ; Humans ; Immunohistochemistry ; In Situ Hybridization ; Lymph Nodes/*metabolism/pathology ; Lymphatic Metastasis ; Male ; Middle Aged ; Neoplasm Recurrence, Local/genetics/metabolism ; Receptor, Epidermal Growth Factor/*analysis/genetics ; Receptor, erbB-2/*analysis/genetics ; Survival Analysis

BACKGROUND: Since 2007 when anaplastic lymphoma kinase (ALK) rearrangements were discovered in non-small cell lung cancer, the ALK gene has received attention due to ALK-targeted therapy, and a notable treatment advantage has been observed in patients harboring the EML4/ALK translocation. However, using ALK-fluorescence in situ hybridization (FISH) as the standard method has demerits such as high cost, a time-consuming process, dependency on interpretation skill, and tissue preparation. We analyzed the histologic findings which could complement the limitation of ALK-FISH test for pulmonary adenocarcinoma. METHODS: Two hundred five cases of ALK-positive and 101 of ALK-negative pulmonary adenocarcinoma from January 2007 to May 2013 were enrolled in this study. The histologic findings and ALK immunohistochemistry results were reviewed and compared with the results of ALK-FISH and EGFR/KRAS mutation status. RESULTS: Acinar, cribriform, and solid growth patterns, extracellular and intracellular mucin production, and presence of signet-ring-cell element, and psammoma body were significantly more often present in ALK-positive cancer. In addition, the presence of goblet cell-like cells and presence of nuclear inclusion and groove resembling papillary thyroid carcinoma were common in the ALK-positive group. CONCLUSIONS: The above histologic parameters can be helpful in predicting ALK rearranged pulmonary adenocarcinoma, leading to rapid FISH analysis and timely treatment.
Adenocarcinoma* ; Carcinoma, Non-Small-Cell Lung ; Complement System Proteins ; Humans ; Immunohistochemistry ; In Situ Hybridization ; In Situ Hybridization, Fluorescence ; Intranuclear Inclusion Bodies ; Lung ; Lymphoma* ; Mucins ; Phosphotransferases* ; Thyroid Neoplasms

BACKGROUND: Pathologic characteristics of the prostatic adenocarcinoma in Korean patients are not clear. We studied 60 cases of radical prostatectomy specimens using mapping analysis in an effort to discover the pathologic characteristics of the Korean prostatic adenocarcinoma. METHODS: A resected prostate was sectioned serially and embedded near-totally. Gleason score, tumor volume or size, capsular extension, involvement of lateral margin, seminal vesicle, vas, apex and base, presence of lymphatic and neural invasion, and presence of high grade prostatic intraepithelial neoplasm (HGPIN) were examined. DNA ploidy and proliferative index were evaluated. RESULTS: Mean values were as follows: age, 63.6 years; serum prostate specific antigen level (sPSA), 24.0 ng/ml; tumor amount (volume, 29.1%; size, 2.4 cm); Gleason score, 7.3; aneuploidy, 23.3%; proliferative index, 14.2%. Involvement rates of apex, base, seminal vesicle, resection margin, nerve and lymphatics were 5.2%, 39.0%, 23.7%, 31.7%, 56.7% and 16.7%, respectively. Rates of multifocal tumors and HGPIN were 43.3% and 63.3%, respectively. The Gleason score was correlated with tumor amount (volume%, p<0.001; size, p<0.01) and tumor extent (T) (p<0.005). Tumor amount was correlated with sPSA (p<0.05) and T (p<0.005). T was correlated with sPSA (p<0.05). CONCLUSION: Korean prostatic adenocarcinomas showed higher Gleason scores, lower HGPIN rates and multifocalities in comparison to western prostatic adenocarcinomas, suggestive of the Korean prostatic adenocarcinomas' late detection.
Adenocarcinoma* ; Aneuploidy ; DNA ; Humans ; Neoplasm Grading ; Pathology ; Ploidies ; Prostate ; Prostate-Specific Antigen ; Prostatectomy ; Prostatic Intraepithelial Neoplasia ; Seminal Vesicles ; Tumor Burden

Cytologic diagnosis of nuclear protein in testis (NUT) midline carcinoma (NMC) is important due to its aggressive behavior and miserable prognosis. Early diagnosis of NMC can facilitate proper management, and here we report two rare cases of thoracic NMC with cytohistologic correlation. In aspiration cytology, the tumor presented with mixed cohesive clusters and dispersed single cells, diffuse background necrosis and many neutrophils. Most of the tumor cells had scanty cytoplasm and medium-sized irregular nuclei, which had fine to granular nuclear chromatin. Interestingly, a few dyskeratotic cells or squamoid cell clusters were present in each case. Biopsy specimen histology revealed more frequent squamous differentiation, and additional immunohistochemistry tests showed nuclear expression of NUT. Because this tumor has a notorious progression and has been previously underestimated in terms of its prevalence, awareness of characteristic findings and proper ancillary tests should be considered in all suspicious cases.
Biopsy ; Chromatin ; Cytoplasm ; Diagnosis ; Early Diagnosis ; Immunohistochemistry ; Lung ; Necrosis ; Neutrophils ; Nuclear Proteins ; Nuts ; Prevalence ; Prognosis ; Testis

BACKGROUND: The amplification of murine double minutes (MDM2) is the primary feature of well-differentiated liposarcomas (WDLPS) and dedifferentiated liposarcomas (DDLPS), while DDIT3 rearrangement is the main one of myxoid liposarcomas (MLPS). Our aim was to evaluate the added value of MDM2 amplification and DDIT3 rearrangement in making a diagnosis and classifying lipogenic tumors. METHODS: Eighty-two cases of liposarcoma and 60 lipomas diagnosed between 1995 and 2010 were analysed for MDM2 amplification and DDIT3 rearrangement using a fluorescence in situ hybridization (FISH). The subtypes of liposarcoma were reclassified according to the molecular results, whose results were reviewed with an analysis of the relevant histologic and immunohistochemical findings. RESULTS: One case of lipoma (1.67%) was reclassified as a WDLPS. Of the liposarcomas, 13.4% (16/82) were reclassified after the molecular testing. Five cases of MLPS were reclassified as four cases of DDLPS and one case of myxoid lipoma. Two cases of WDLPS were reclassified as one case of spindle cell lipoma and another case of myxofibrosarcoma. Four cases of DDLPS were reclassified as two cases of leiomyosarcoma, one case of angiomyolipoma and another case of fibroinflammatory lesion. Of the six cases of pleomorphic liposarcoma, five were reclassified as DDLPS. CONCLUSIONS: In our series, a critical revision of diagnosis was found at a rate of 3.5% (5/142) after a review of the lipomatous lesions. The uses of molecular testing by MDM2 and DDIT3 FISH were valuable to make an accurate subtyping of liposarcomas as well as to differentiate WDLPS from benign lipomatous tumor.
Angiomyolipoma ; Fluorescence ; In Situ Hybridization ; In Situ Hybridization, Fluorescence ; Leiomyosarcoma ; Lipoma ; Liposarcoma ; Liposarcoma, Myxoid

BACKGROUND: KRAS is one of commonly mutated genetic "drivers" in non-small cell lung cancers (NSCLCs). Recent studies indicate that patients with KRAS-mutated tumors do not benefit from adjuvant chemotherapy, so there is now a focus on targeting KRAS-mutated NSCLCs. A feasible mutation detection method is required in order to accurately test for KRAS status. METHODS: We compared direct Sanger sequencing and the peptide nucleic acid (PNA)-mediated polymerase chain reaction (PCR) clamping method in 134 NSCLCs and explored associations with clinicopathological factors. Next-generation sequencing (NGS) was used to validate the results of discordant cases. To increase the resolution of low-level somatic mutant molecules, PNA-mediated PCR clamping was used for mutant enrichment prior to NGS. RESULTS: Twenty-one (15.7%) cases were found to have the KRAS mutations using direct sequencing, with two additional cases by the PNA-mediated PCR clamping method. The frequencies of KRAS mutant alleles were 2% and 4%, respectively, using conventional NGS, increasing up to 90% and 89%, using mutant-enriched NGS. The KRAS mutation occurs more frequently in the tumors of smokers (p=.012) and in stage IV tumors (p=.032). CONCLUSIONS: Direct sequencing can accurately detect mutations, but, it is not always possible to obtain a tumor sample with sufficient volume. The PNA-mediated PCR clamping can rapidly provide results with sufficient sensitivity.
Alleles ; Carcinoma, Non-Small-Cell Lung* ; Chemotherapy, Adjuvant ; Constriction* ; Humans ; Lung Neoplasms ; Peptide Nucleic Acids ; Polymerase Chain Reaction*