小林 一博

PURPOSE: This study aimed to compare the differences in the imaging findings for dedifferentiated liposarcoma (DDLS) and myxoid liposarcoma (MLS). METHODS: The study included 30 patients with histopathologically confirmed DDLS and 13 patients with MLS. All DDLSs and MLSs were diagnosed immunohistochemically using MDM2 and DDIT3 staining, respectively. Conventional MRI, CT, and 18F-fluorodeoxyglucose-positron emission tomography/CT findings were retrospectively evaluated and compared between the 2 pathologies. RESULTS: The median age of patients with DDLS was higher than that of patients with MLS (74 vs. 46 years, P < 0.01). In 10 DDLSs and 7 MLSs with fatty areas, the well-differentiated liposarcoma-like fatty areas were more common in DDLS than in MLS (70% vs. 14%), whereas septal/linear fatty areas were less common in DDLS than in MLS (30% vs. 86%, P < 0.05). The T2-hyperintense area of non-fatty area was less common in DDLS than in MLS (50% vs. 92%, P < 0.05), and the tumor-to-muscle signal intensity ratio of non-fatty areas on T2-weighted images was lower in DDLS than in MLS (3.18 vs. 5.92, P < 0.01). Apparent diffusion coefficient value was lower in DDLS than in MLS (1.29 vs. 2.10 × 10-3mm2/sec, P < 0.01). Unenhanced CT attenuation of non-fatty area was greater in DDLS than in MLS (33 vs. 19 Hounsfield unit, P < 0.01). CONCLUSION: MRI features are valuable in differentiating MLS from DDLS. Younger age, septal/linear fatty areas, and high signal intensity of non-fatty areas on T2-weighted images were useful for diagnosing MLS.

The histological classification of gastric adenocarcinoma influences its prognostic outcomes and therapeutic strategies. Although fibroblast growth factor (FGF)10 is important for gastric morphogenesis, its use as a molecular marker of gland-forming differentiation pattern remains undefined. The present study examined 117 surgically resected gastric adenocarcinoma specimens using immunohistochemical analysis to evaluate the expression of FGF10 and FGF receptor 2 (FGFR2). Expression patterns in tumor cells and the surrounding stroma were assessed using a four-tier scale. Associations between marker expression and histological differentiation were analyzed by multivariable ordinal logistic regression, adjusting for age, human epidermal growth factor receptor 2 and epidermal growth factor receptor status. Elevated FGF10 expression was significantly associated with well-differentiated, gland-forming histological subtypes, particularly in moderately differentiated tubular adenocarcinoma [adjusted odds ratio (OR) in tumor cells: 1.749, 95% confidence interval (CI) 1.231-2.487, P=0.002; adjusted OR in stroma: 2.418, 95% CI 1.123-5.206, P=0.024]. Conversely, FGFR2 expression showed no association with differentiation pattern (adjusted OR: 0.908, 95% CI 0.452-1.824, P=0.788). Survival analysis revealed no significant relationship between FGF10 or FGFR2 expression level and overall patient survival [hazard ratio (HR) for FGF10 in tumor cells: 0.823, 95% CI 0.640-1.057, P=0.127; HR for FGF10 in stroma: 0.675, 95% CI 0.385-1.183, P=0.170; HR for FGFR2 in tumor cells: 1.080, 95% CI 0.559-2.085, P=0.819]. FGF10 may thus be a promising molecular marker of gland-forming differentiation pattern in gastric adenocarcinoma, offering valuable insights for refining its histopathological classification. These findings may contribute to the development of stratification biomarkers for personalized therapeutic approaches, particularly for the selection of molecular-targeted therapies. The absence of an association with overall survival, however, highlights the need for further investigations into the underlying mechanisms and their broader clinical significance.

A 50-year-old man presented with a subcutaneous mass on the posterior neck. A skin biopsy suggested lipoma, leading to observation. Over the next 5 years, the tumor gradually enlarged. Clinical evaluation found the tumor to be a soft, mobile mass of 10 × 7 cm. Magnetic resonance imaging showed the lesion to be cystic, with hyperintense mural nodules on T2-weighted sequences, and with scattered, hyperintense foci indicative of fatty components on T1-weighted imaging. Fat-suppressed contrast-enhanced T1-weighted imaging revealed moderately enhanced mural nodules. Surgical resection revealed a well-circumscribed cystic mass containing fluid, surrounded by a fibrous capsule. We suspected spindle cell lipoma associated with fluid and performed a marginal resection. Gross examination showed a heterogeneous mixture of reddish-brown and yellowish zones interspersed with fissures. Histological analysis revealed a leaf-like or reticular pattern, with slender, spindle-shaped cells and ropey collagens within a mucinous matrix, along with mature adipocytes. There were many irregular, branching, cleft-like vascular spaces lined by flattened cells. Immunohistochemical staining revealed tumor cells positive for CD34 and negative for retinoblastoma protein. Luminal endothelial-like cells showed positivity for D2-40, CD31, and erythroblastosis transformation-specific regulated gene 1. Based on these findings, the diagnosis of pseudoangiomatous spindle-cell lipoma was confirmed, with the luminal endothelial-like cells exhibiting characteristics of lymphatic endothelium.