Prevalence of Incidentally Detected Spondylolysis in Children

Purpose@#To assess the prevalence of incidentally detected lumbar spondylolysis in children. @*Materials and Methods@#We retrospectively reviewed the data of 809 patients under the age of 11 years (mean age, 7.0 ± 2.7 years; boys:girls = 479:330) who underwent abdominal and pelvic CT between March 2014 and December 2018. We recorded the presence, level, and laterality (unilateral or bilateral) of spondylolysis. Patients were divided into two groups based on the presence of spondylolysis: the spondylolysis (SP) and non-SP groups. @*Results@#In total, 21 cases of spondylolysis were detected in 20 patients (20/809, 2.5%). The mean age of the SP group was higher than that of the non-SP group (7.8 ± 1.8 vs. 6.9 ± 2.7 years, p > 0.05). The prevalence of spondylolysis in boys was higher than that in girls (15/479 [3.1%] vs. 5/330 [1.5%], p > 0.05). The prevalence of spondylolysis in school-age children (6–10 year olds) was higher than that in preschool-age children (0–5 year olds) (17/538 [3.2%] vs. 3/271 [1.1%], p > 0.05). L5 was the most common level of spondylolysis (76.2%); one 8-year-old boy had twolevel spondylolysis. One case of isthmic spondylolisthesis was detected in a 10-year-old boy (1/809, 0.1%). There were 11 unilateral spondylolysis cases (11/21, 52.4%). @*Conclusion@#In our study, the prevalence of spondylolysis in children under the age of 11 was 2.5%. The prevalence was higher in boys than in girls and in school-age than in preschool-age children, despite the lack of any statistically significant differences.

Intraosseous Hibernoma: A Rare and Unique Intraosseous Lesion

BACKGROUND: Hibernoma is a rare benign tumor of adults that is composed of multivacuolated adipocytes resembling brown fat cells. Hibernoma typically occurs in soft tissue, and intraosseous examples are very rare. Intraosseous hibernomas can radiologically mimic metastatic carcinoma and other tumorous conditions. METHODS: To collect the intraosseous hibernomas, we searched the pathologic database and reviewed the hematoxylin and eosin (H&E)–stained slides of bone biopsy samples performed to differentiate radiologically abnormal bone lesions from 2006 to 2016. A total of six intraosseous hibernoma cases were collected, and clinical and radiological information was verified from electronic medical records. H&E slide review and immunohistochemical staining for CD68, pan-cytokeratin, and S-100 protein were performed. RESULTS: Magnetic resonance imaging of intraosseous hibernomas showed low signal intensity with slightly hyperintense foci on T1 and intermediate to high signal intensity on T2 weighted images. Intraosseous hibernomas appeared as heterogeneous sclerotic lesions with trabecular thickening on computed tomography scans and revealed mild hypermetabolism on positron emission tomography scans. Histopathologically, the bone marrow space was replaced by sheets of multivacuolated, foamy adipocytes resembling brown fat cells, without destruction of bone trabeculae. In immunohistochemical analysis, the tumor cells were negative for CD68 and pan-cytokeratin and positive for S-100 protein. CONCLUSIONS: Intraosseous hibernoma is very rare. This tumor can be overlooked due to its rarity and resemblance to bone marrow fat. Pathologists need to be aware of this entity to avoid misdiagnosis of this rare lesion.

Implication of PHF2 Expression in Clear Cell Renal Cell Carcinoma

BACKGROUND: Clear cell renal cell carcinoma (CCRCC) is presumed to be associated with adipogenic differentiation. Histone modification is known to be important for adipogenesis, and the function of histone demethylase plant homeodomain finger 2 (PHF2) has been noted. In addition, PHF2 may act as a tumor suppressor via epigenetic regulation of p53 and is reported to be reduced in colon cancer and stomach cancer tissues. In this study, we examined PHF2 expression in CCRCC specimens by immunohistochemistry. METHODS: We studied 254 CCRCCs and 56 non-neoplastic renal tissues from patients who underwent radical or partial nephrectomy between 2000 and 2003 at the Seoul National University Hospital. Tissue microarray blocks were prepared, and immunohistochemical staining for PHF2 was performed. RESULTS: Among 254 CCRCC cases, 150 cases (59.1%) showed high expression and 104 cases (40.1%) showed low expression. High expression of PHF2 was significantly correlated with a low Fuhrman nuclear grade (p < .001), smaller tumor size (p < .001), low overall stage (p = .003), longer cancer-specific survival (p = .002), and progression-free survival (p < .001) of the patients. However, it was not an independent prognostic factor in multivariate analysis adjusted for Fuhrman nuclear grade and overall stage. CONCLUSIONS: Our study showed that low expression of PHF2 is associated with aggressiveness and poor prognosis of CCRCC.

Comparison of the FDA and ASCO/CAP Criteria for HER2 Immunohistochemistry in Upper Urinary Tract Urothelial Carcinoma

BACKGROUND: Human epidermal growth factor receptor 2 (HER2) is one of the known oncogenes in urothelial carcinoma. However, the association between HER2 and the prognosis of upper urinary tract urothelial carcinoma (UUTUC) has not yet been fully clarified. The aim of this study was to evaluate HER2 expression using the United States Food and Drug Administration (FDA) criteria and American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) criteria and compare their prognostic significance in UUTUC. METHODS: HER2 expression was evaluated in 144 cases of UUTUC by immunohistochemistry (IHC) using tissue microarrays. We separately analyzed HER2 expression using the FDA and ASCO/CAP criteria. The IHC results were categorized into low (0, 1+) and high (2+, 3+) groups. RESULTS: Using the FDA criteria, 94 cases were negative, 38 cases were 1+, nine cases were 2+, and three cases were 3+. Using the ASCO/CAP criteria, 94 cases were negative, 34 cases were 1+, 13 cases were 2+, and three cases were 3+. Four cases showing 2+ according to the ASCO/CAP criteria were reclassified as 1+ by the FDA criteria. High HER2 expression by both the FDA criteria and ASCO/CAP criteria was significantly associated with International Society of Urological Pathology high grade (p = .001 and p < .001). The high HER2 expression group classified with the FDA criteria showed significantly shorter cancer-specific survival (p = .004), but the HER2 high and low expression groups classified with the ASCO/CAP criteria did not show significant differences (p = .161) in cancer-specific survival. CONCLUSIONS: HER2 high expression groups were significantly associated with shorter cancer-specific survival, and our study revealed that the FDA criteria are more suitable for determining HER2 expression in UUTUC.