Secondary Peripheral Dedifferentiated Chondrosarcoma: A Case Report with Special Emphasis on the Radiology/Pathology Correlation.

CASE: In a 54-year-old man, imaging findings suggested a malignant bone tumor having 2 distinct components of the left ilium. Histopathologically, the resected tumor was diagnosed as dedifferentiated chondrosarcoma (CS) arising in secondary peripheral CS. CONCLUSION: Dedifferentiated CS consists of a high-grade noncartilaginous sarcoma adjacent to a preexisting low-grade CS, among which the peripheral type is extremely rare. Because the bimorphic imaging findings reflected the dedifferentiated area and the CS area, they were considered useful for diagnosis. In addition, the dedifferentiated area was localized to the tumor's edge, suggesting that the dedifferentiation originated from the cartilage cap.

The Expression of Insulin-Like Growth Factor II Messenger RNA-Binding Protein 3 Upregulated in Intradural Extramedullary Schwannomas.

Introduction: Tumor size is an important factor in determining the appropriate clinical management of intradural-extramedullary schwannoma. A tumor volume reduction may be achieved by conservative targeted therapy instead of invasive surgery if a molecular event related to tumor size is discovered. Insulin-like growth factor II messenger RNA-binding protein 3 (IMP3), an oncofetal tumor-associated antigen that is expected to be a target for immunotherapy, was focused on in this study. Methods: The IMP3 status was assessed by immunohistochemistry in 64 samples of intradural-extramedullary schwannoma, and the correlation between IMP3 expression and tumor size was evaluated. Results: Immunohistochemically, high IMP3 expression was observed in ～85% of schwannomas. The maximum tumor diameter of the high IMP3 expression group was significantly larger than that of the low IMP3 expression group (34.3 mm vs 18.5 mm, p=0.002). The receiver operating characteristic curve demonstrated that a maximum tumor diameter of 24 mm was a predictable factor for IMP3 expression (sensitivity, 0.7; 1-specificity, 0.2; area under the curve, 0.82). Conclusions: Upregulated IMP3 expression was associated with large tumor size, suggesting a possible therapeutic approach.

Standardization of evaluation method and prognostic significance of histological response to preoperative chemotherapy in high-grade non-round cell soft tissue sarcomas.

BACKGROUND: Preoperative chemotherapy is widely applied to high-grade localized soft tissue sarcomas (STSs); however, the prognostic significance of histological response to chemotherapy remains controversial. This study aimed to standardize evaluation method of histological response to chemotherapy with high agreement score among pathologists, and to establish a cut-off value closely related to prognosis. METHODS: Using data and specimens from the patients who had registered in the Japan Clinical Oncology Group study, JCOG0304, a phase II trial evaluating the efficacy of perioperative chemotherapy with doxorubicin (DOX) and ifosfamide (IFO), we evaluated histological response to preoperative chemotherapy at the central review board. RESULTS: A total of 64 patients were eligible for this study. The percentage of viable tumor area ranged from 0.1% to 97.0%, with median value of 35.7%. Regarding concordance proportion between pathologists, the weighted kappa coefficient (κ) score in all patients was 0.71, indicating that the established evaluation method achieved substantial agreement score. When the cut-off value of the percentage of the residual tumor area was set as 25%, the p-value for the difference in overall survival showed the minimum value. Hazard ratio of the non-responder with percentage of the residual tumor < 25%, to the responder was 4.029 (95% confidence interval 0.893-18.188, p = 0.070). CONCLUSION: The standardized evaluation method of pathological response to preoperative chemotherapy showed a substantial agreement in the weighted κ score. The evaluation method established here was useful for estimating of the prognosis in STS patients who were administered perioperative chemotherapy with DOX and IFO. TRIAL REGISTRATION: UMIN Clinical Trials Registry C000000096. Registered 30 August, 2005 (retrospectively registered).

Histological background of dedifferentiated solitary fibrous tumour.

AIMS: Dedifferentiation is a histological phenomenon characterised by abrupt transition of histology to a sarcomatous component with high-grade malignant potential in solitary fibrous tumour (SFT). The authors histologically reviewed SFT cases to reveal the histological background of dedifferentiated SFTs. METHODS: Clinicopathological and histopathological findings of 145 SFT cases were reviewed. Immunohistochemical staining and genetic analysis were also performed. RESULTS: The non-dedifferentiated components showed a cellular component in 45 of 145 (31%), high mitotic rate (≥4/10 high-powered field) in 12 of 145 (8.2%) tumours, necrosis in 7 of 145 (4.8%) tumours, multinodular growth pattern in 39 of 132 (29.5%) available tumours and intratumoural fibrous septa in 37 of 131 (28.2%). Immunohistochemically, the non-dedifferentiated components were positive for CD34 in 128 of 141 (90.7%), bcl-2 in 101 of 133 (75.9%), nuclear pattern of ß-catenin in 64 of 127 (50.3%) and p16 in 22 of 140 (15.7%). Loss of Rb protein expression was detected in 17 of 110 (15.4%) cases. Statistically, cellular component, multinodular structure, p16 overexpression and Rb protein loss were significantly associated with dedifferentiation. Moreover, cellular component and multinodular structure were significantly associated with p16 overexpression and Rb protein loss. All the non-deddifferentiated components showed wild type of p53 expression. The dedifferentiated components of all 10 dedifferentiated tumours presented positivity for p16 in 9 of 10 (90%) and mutational type of p53 in 5 of 10 (50%). Loss of Rb protein expression was detected in 6 of 10 (60%). CONCLUSIONS: The authors propose that cellular or multinodular transformation may be associated with dedifferentiation. They also suggest that cellular and multinodular transformation may be associated with p16 overexpression and Rb downregulation.

Histological and immunohistochemical features and genetic alterations in the malignant progression of giant cell tumor of bone: a possible association with TP53 mutation and loss of H3K27 trimethylation.

In rare cases, giant cell tumor of bone (GCTB) can undergo primary or secondary malignant transformation to malignant giant cell tumor of bone (MGCTB), but the details of the molecular alterations are still unclear. The present study aimed to elucidate the clinicopathologic and molecular features of MGCTBs based on immunohistochemistry, fluorescence in situ hybridization (FISH) and next generation sequencing (NGS) of nine MGCTBs (five primary and four secondary). Seven (78%) of 9 MGCTBs were immunohistochemically positive for H3.3 G34W. In two (22%) patients, although GCTB components were focally or diffusely positive for H3.3 G34W, their malignant components were entirely negative for H3.3 G34W, which was associated with heterozygous loss of H3F3A by FISH. NGS on four MGCTBs revealed pathogenic mutations in TP53 (n = 3), EZH2 (n = 1) and several other genes. Immunohistochemical analysis of the nine MGCTBs confirmed the p53 nuclear accumulation (n = 5) and loss of H3K27me3 expression (n = 3) and showed that they were mutually exclusive. In addition, four (80%) of five cases of pleomorphic or epithelioid cell-predominant MGCTBs were positive for p53, while three (75%) of four cases of spindle cell-predominant MGCTBs were negative for trimethylation at lysine 27 of histone 3 (H3K27me3). The results suggested that p53 alteration and dysfunction of histone methylation as evidenced by H3K27me3 loss may play an important role in the malignant progression of GCTB, and might contribute to the phenotype-genotype correlation in MGCTB. The combined histologic, immunohistochemical and molecular information may be helpful in part for the diagnosis of challenging cases.

Clinicopathological and prognostic significance of H3K27 methylation status in malignant peripheral nerve sheath tumor: correlation with skeletal muscle differentiation.

Malignant peripheral nerve sheath tumor (MPNST) is a very aggressive peripheral nerve sheath-derived sarcoma, which is one of the most difficult tumors to diagnose due to its wide spectrum of histological findings and lack of specific immunohistochemical markers. Recently, it has been reported that losses of expression of H3K27me3 and H3K27me2 caused by PRC2 dysfunction may be useful diagnostic markers for MPNST, but there is no consensus on their clinicopathological significance. Here, we investigated the relationship between loss of H3K27 methylation and various parameters and clarified the clinicopathological significance of such loss. We analyzed the clinicopathological and immunohistochemical features in 84 MPNST cases. Complete losses of H3K27me3 and H3K27me2 were observed in 37 (44%) and 29 (35%) cases, respectively. Losses of H3K27me3 and H3K27me2 were significantly correlated with myogenic immunopositivity (H3K27me3 vs. desmin, P = 0.0051; H3K27me3 vs. myogenin, P = 0.0009; H3K27me2 vs. myogenin, P = 0.042). Meanwhile, there were significant correlations between preservation of immunohistochemical neurogenic markers and intact H3K27me3 and H3K27me2 (H3K27me3 vs. S-100 protein, P = 0.0019; H3K27me3 vs. SOX10, P = 0.014; H3K27me2 vs. S-100 protein, P = 0.0011; H3K27me2 vs. SOX10, P = 0.0087). In multivariate analysis, local recurrence, distant metastasis, high FNCLCC grade, and loss of SOX10 expression were independent prognostic factors for overall survival. H3K27me3 and H3K27me2 expression was retained in all 26 cases of rhabdomyosarcoma non-alveolar subtype. In conclusion, we suggest that H3K27me3 and H3K27me2 immunonegativity is useful but not definitive for diagnosing MPNST. Complete loss of H3K27 methylation may be involved in aggressive transdifferentiation from neural differentiation to skeletal muscle differentiation in MPNST.

PD­L1 and IDO­1 expression in undifferentiated pleomorphic sarcoma: The associations with tumor infiltrating lymphocytes, dMMR and HLA class I.

The prognosis of undifferentiated pleomorphic sarcoma (UPS) is generally unfavorable. Recently, clinical trials such as SARC028 demonstrated the utility of cancer immunotherapy for soft tissue sarcomas. The aim of the present study was to assess the expression of PD­L1 and IDO­1 as prognostic factors and therapeutic targets. A total of 52 primary UPS cases were retrieved and two UPS cell lines were utilized for supplementary analysis. Immunohistochemical staining of anti­PD­L1 (28­8), IDO­1, CD8, CD4, CD3, HLA class I, MSH2, MSH6, MLH1 and PMS2 was carried out. Immunohistochemically, 19 of 52 (36.5%) cases showed PD­L1 expression at least focally (≥1%) and 5 of 52 (9.62%) showed strong PD­L1 expression (≥50%). Overall, 25 of 52 (48.1%) cases expressed IDO­1 (≥1%). Two tumors were evaluated as having deficient mismatch repair and six tumors as having the loss of HLA class I. PD­L1 expression (≥1%) was significantly related to the infiltration of CD8­ and CD3­positive lymphocytes, but strong PD­L1 expression (≥50%) did not present a significant relationship with tumor­infiltrating lymphocytes. IDO­1 expression was also associated with CD8­, CD4­, and CD3­positive lymphocytes. In vitro, both PD­L1 and IDO­1 were induced by IFN­Î³ stimulation. In survival analysis, strong PD­L1 expression (≥50%) was a significant poor prognostic factor, while IDO­1 expression (≥1%) was a favorable one. In conclusion, UPS was shown to frequently express PD­L1 and IDO­1. It was suggested that PD­L1 expression (≥50%) and IDO­1 expression are poor and favorable prognostic factors of UPS patients, respectively.

PD-L1 and IDO1 expression and tumor-infiltrating lymphocytes in osteosarcoma patients: comparative study of primary and metastatic lesions.

PURPOSE: Programmed death ligand 1 (PD-L1) and indoleamine 2,3-dioxygenase 1 (IDO1) are immunosuppressive proteins known to be associated with poor prognosis in various cancers. However, their expression and clinical relevance in osteosarcoma remain unknown. In this study, the relationships of PD-L1 and IDO1 expression with clinicopathological features and prognosis were explored. METHODS: The expression of PD-L1, IDO1, CD3, CD4, and CD8 in 112 formalin-fixed, paraffin-embedded tumor tissues collected by biopsy or surgical resection from 56 osteosarcoma patients was evaluated immunohistochemically. Moreover, four osteosarcoma cell lines were evaluated for the effects of IFNγ on PD-L1 and IDO1 mRNA expression by real-time reverse-transcription polymerase chain reaction. RESULTS: In pre-neoadjuvant chemotherapy (NAC) primary specimens, 10 cases (17%) showed PD-L1 expression and 12 (21%) showed IDO1 expression. Six of ten cases (60%) with PD-L1 positivity co-expressed IDO1. In post-NAC metastatic lesions, the frequency of immunoexpression of PD-L1 and IDO1 was increased compared with that in pre-NAC specimens. PD-L1 and/or IDO1 expression was not associated with poor prognosis. PD-L1 immunoexpression was significantly associated with the infiltration of CD3+ T cells, CD4+ T cells, and CD8+ T cells; while, IDO1 immunoexpression was significantly associated with the infiltration of CD3+ T cells and CD4+ T cells. In all osteosarcoma cell lines, PD-L1 and IDO1 expression was upregulated by stimulation with IFNγ. CONCLUSION: Our results suggest that the PD-L1 and IDO1 immune checkpoint inhibitors may provide clinical benefit in osteosarcoma patients with metastatic lesions after conventional chemotherapy.

Comparative Study of Myxofibrosarcoma With Undifferentiated Pleomorphic Sarcoma: Histopathologic and Clinicopathologic Review.

Myxofibrosarcoma (MFS) is a malignant fibroblastic/myofibroblastic neoplasm with the prominent myxoid area. It has the clinical features of frequent local recurrence and occasional distant metastasis. Morphologically, MFS is occasionally difficult to distinguish from undifferentiated pleomorphic sarcoma (UPS), especially in the case of high-grade MFS. Here, we reviewed clinical and histologic data of 162 MFS cases and 43 UPS cases. MFS was distinguished from UPS with the criterion of 10% myxoid area as a cutoff value. Overall, 52 MFS (34.4%) and 9 UPS (20.9%) cases showed local recurrence, 18 MFS (12.2%) and 19 UPS (44.2%) cases developed distant metastasis, and 13 MFS (9.5%) and 14 UPS (32.6%) cases resulted in tumor-related death. Statistically, MFS had a better prognosis than UPS. Moreover, MFS with less myxoid area had a tendency to present a poorer prognosis. FNCLCC grade was a statistically significant prognostic factor (distant metastasis: P=0.0021, tumor-related death: P=0.0021). Cellularity and nuclear atypia had only a statistical tendency for associations with a poorer prognosis. The overall survival rate of MFS after transformation into a UPS-like condition (<10% myxoid area) was close to that of UPS. It was suggested that MFS is a biologically distinct tumor from UPS, and MFS with less myxoid area had a tendency to present a poorer prognosis. We considered that evaluation of the amount of myxoid area, cellularity, and nuclear atypia may be important as prognostic predictors. MFS may become similar to histologic malignancy of UPS in terms of morphology and biology via local recurrence.

Clinicopathological review of solitary fibrous tumors: dedifferentiation is a major cause of patient death.

Solitary fibrous tumor (SFT) is a soft-tissue neoplasm of intermediate malignant potential, presenting a wide histopathological spectrum. Poorer prognosis of hemangiopericytoma of the central nervous system (CNS), hypoglycemic SFT, and dedifferentiation are well-known characters of SFT, but their clinical significance were not demonstrated enough by large-sized study. Here, the clinicopathological features of SFTs are reviewed and the relationship between genetics and clinicopathological features is examined using 145 SFT cases. All cases were STAT6 IHC-positive and/or NAB2-STAT6 fusion gene-positive. Tumor location was classified into three categories: 30 pleuropulmonary, 96 non-pleuropulmonary/non-central nervous system (CNS), and 18 CNS tumors. The tumor developed recurrence in 21 of 93 available cases (22.5%), metastasis in 11 of 93 (11.8%), and tumor death in 9 of 93 (9.6%). Hypoglycemia occurred in 2 primary tumors and 1 metastatic tumor among 63 reviewable cases, and dedifferentiation occurred in 10 cases (6.8%) including 6 primary tumors, 2 recurrent tumors, and 2 metastatic tumors. Recurrence was positively associated with CNS location (p = 0.0109) and hypoglycemia (p = 0.001); metastasis was positively associated with CNS location (p = 0.0231), hypoglycemia (p < 0.0001), and dedifferentiation (p < 0.0001), while metastasis was negatively correlated with pleural location (p = 0.0471). Tumor death was positively associated with male sex (p = 0.0154), larger size (p = 0.0455), hypoglycemia (p < 0.0001), and dedifferentiation (p < 0.0001). Multivariate analysis revealed independent statistical significance of dedifferentiation for overall survival (p = 0.0467). Exon variant of the fusion gene had no statistical correlation with clinical outcome. In conclusion, dedifferentiation is a major prognostic factor of SFT, and specific location such as cerebromeningeal and intra-abdominal site and hypoglycemia also had a high risk for unfavorable prognosis.

Immunohistochemical evaluation of H3K27 trimethylation in malignant peripheral nerve sheath tumors.

The histological definitive diagnosis of malignant peripheral nerve sheath tumor (MPNST) is quite difficult because the morphological features are not specific and no useful immunohistochemical marker has been identified. Loss-of-function mutations in EED or SUZ12, which encode the core subunit of polycomb repressive complex 2 (PRC2), were reported in MPNSTs, and the mutations were shown to cause inactivation of PRC2, leading to loss of trimethylation of histone H3 at lysine 27 (H3K27me3). Immunohistochemistry of H3K27me3 is expected to be a specific marker for MPNSTs. We evaluated immunohistochemical expression of H3K27me3 in MPNSTs with heterologous components and metachronous cases of MPNSTs. Among 145 MPNST samples, 50 (34.5%) showed complete loss of staining, and 45 (31.0%) showed partial loss of staining. Regarding the backgrounds of MPNSTs, 43 patients of neurofibromatosis type 1 (NF-1)-associated MPNST demonstrated 19 (44.2%) complete and 12 (27.9%) partial loss of H3K27me3. Among MPNSTs with heterologous component, almost all of MPNSTs with epithelioid differentiation (8/9 samples, 88.9%) retained H3K27me3, and malignant Triton tumors without epithelioid component lacked H3K27me3 at high rate (91.7%). Five of 20 metachronous MPNST cases showed significantly reduced expression of H3K27me3 between primary and later-occurring tumors, but in some cases increased expression of H3K27me3 in the clinical course (such as complete loss to partial loss) was observed. If the tumors are recurrent or metastatic, H3K27me3 expression should be reduced or at least maintained because loss of H3K27me3 is due to genetic mutation of EED or SUZ12. MPNSTs, especially those associated with NF-1, can occur in heterochronous and multiple patterns, and the identification of increased expression of H3K27me3 during a patient's clinical course can be helpful for determining whether the tumors are heterochronous, multiple or not. As heterochronous and multiple tumors may show lower malignancy compared to recurrent or metastatic tumors, favorable prognosis may be expected when H3K27me3 expression is increased.

Histopathological and genetic review of phosphaturic mesenchymal tumours, mixed connective tissue variant.

AIMS: Phosphaturic mesenchymal tumour, mixed connective tissue variant (PMT-MCT), is a tumour of uncertain differentiation, characterised by 'smudgy/grungy' calcification and vitamin D-resistant phosphaturic osteomalacia. Fibroblast growth factor (FGF)23 is recognised as a reliable marker of PMT-MCT, but quantitative evaluation has never been performed. We reviewed cases of tumour-associated osteomalacia or histologically definitive PMT-MCT without osteomalacia using histological, immunohistochemical and genetic methods and evaluated the diagnostic significance of these findings. METHODS AND RESULTS: A total of 19 tumours from 14 cases diagnosed previously as PMT-MCT were retrieved, on which immunohistochemical staining, reverse transcription-polymerase chain reaction (RT-PCR) and fluorescence in-situ hybridisation (FISH) analysis were performed. Histologically, fibrous capsule, calcification and giant cell reaction tended to be observed in soft-tissue PMT-MCT, while PMT-MCT of bone and multiple PMT-MCT showed an infiltrative growth pattern. The immunohistochemical results were as follows: the tumour cells were positive for FGF23 (nine of 12, 75%), FGFR1 (11 of 11, 100%), CD56 (12 of 14, 85.7%) and E26 oncogene homologue (ERG) (5 of 13, 38.4%). The sole malignant tumour was positive for p53. FGF23 mRNA was detected in seven of 14 formalin-fixed paraffin-embedded (FFPE) specimens and all five frozen specimens by RT-PCR. The level of FGF23 mRNA, which was determined by real-time PCR, varied among the phosphaturic cases. Two of 17 tumours were positive for FGFR1 gene rearrangement. CONCLUSIONS: It was considered that PMT-MCT is a histopathological entity with or without phosphaturia, with varying levels of FGF23 mRNA, and with or without fibronectin 1 (FN1)-FGFR1 fusion gene. The authors propose that the histology of PMT-MCT differs depending on its location, such as bone or soft tissue, which could complicate the differential diagnosis.

Inverted V-shaped high tibial osteotomy for severe tibia vara associated with Turner syndrome: A case report and review of literature.

INTRODUCTION: Severe cases of genu varum represent a major challenge in obtaining normal configuration of the proximal tibia and overall limb alignment. PRESENTATION OF CASE: We performed inverted V-shaped high tibial osteotomy (HTO) by using a locking plate for recurrent severe bilateral tibia vara in a 15-year-old female patient with Turner syndrome. Preoperative medial proximal tibial angle (MPTA) and standing femorotibial angle (FTA) of the right/left legs were 67°/69° and 197°/203°, respectively. In order to obtain overall neutral alignment, the correction angle in the right/left knees was required to be 23°/32°. Preoperative planning demonstrated that inverted V-shaped HTO could provide sufficient correction angle with large bone stock and wide bony contact. A postoperative full-standing radiograph showed that the mechanical axes passed through the center of right/left knees with 87°/88° of MPTA. DISCUSSION: Inverted V-shaped HTO has advantages, as it requires a smaller amount of bone resection and smaller opening gap compared to the closing-wedge and opening-wedge osteotomies. CONCLUSION: Inverted V-shaped HTO can be a useful surgical method to treat severe tibia vara in order to obtain adequate configuration of the proximal tibia and overall limb alignment.

Diagnostic utility of histone H3.3 G34W, G34R, and G34V mutant-specific antibodies for giant cell tumors of bone.

Giant cell tumors of bone (GCTBs) are characterized by mononuclear stromal cells and osteoclast-like giant cells; up to 95% have H3F3A gene mutation. The RANKL inhibitor denosumab, when used for the treatment of GCTB, leads to histological changes such as new bone formation and giant cell depletion. Here we assessed the diagnostic utility of immunohistochemical staining with the antibodies against histone H3.3 G34W, G34R and G34V mutant proteins for GCTB and other histologically similar bone and joint lesions. H3.3 G34W, G34R and G34V expressions were detected in mononuclear stromal cells in 47/51 (92%), 1/51 (2%) and 3/51 (6%) cases of primary GCTBs, respectively, in a mutually exclusive manner. All recurrent/metastatic GCTBs (n=14), post-denosumab GCTBs (n=8) and secondary malignant GCTBs (n=2) were positive for H3.3 G34W. The immunohistochemical results were essentially correlated with the H3F3A genotype determined by mutation analysis. In post-denosumab GCTBs, H3.3 G34W expression was seen in immature bone-forming cells. H3.3 G34W, G34R and G34V were negative in 121/122 cases of non-GCTB, including chondroblastoma, osteosarcoma, primary aneurysmal bone cyst and other giant cell-rich lesions. The exception was a single case of undifferentiated high-grade pleomorphic sarcoma that was positive for H3.3 G34W, suggesting the possibility of sarcomatous overgrowth of primary malignant GCTB. Therefore, H3.3 G34W/R/V mutant-specific antibodies are useful surrogate markers for the H3F3A genotype and helpful for the diagnosis of GCTB and its variants. The expression of H3.3 G34W mutant protein in post-denosumab GCTB suggests that neoplastic stromal cells may play a role in new bone formation.

Comparison between retroperitoneal leiomyosarcoma and dedifferentiated liposarcoma.

It is important to distinguish between leiomyosarcoma (LMS) and dedifferentiated liposarcoma (DDLS) in the retroperitoneum. The dedifferentiated component of DDLS shows an LMS-like morphology in some cases; thus, detailed evaluation is necessary to achieve an accurate diagnosis. Immunohistochemically, MDM2 and myogenic markers provide clues for the diagnoses. However, immunoreactivity for MDM2 and myogenic markers has not been well studied in retroperitoneal LMS and DDLS. Here, we compared the clinicopathological data of 20 retroperitoneal tumors initially diagnosed as LMS with that of 36 cases of retroperitoneal DDLS and conducted an immunohistochemical study. Four (20%) of the cases initially diagnosed as LMS were immunoreactive for MDM2. Fifteen cases (41.7%) of DDLS showed positive expression of two or more myogenic markers. The patients with LMS with MDM2 overexpression were older than the patients with LMS without MDM2 overexpression (P=0.0328). LMS with MDM2 overexpression showed a worse prognosis than DDLS (P=0.0408). No significant difference in prognosis was found between LMS without MDM2 overexpression and DDLS with myogenic differentiation. In conclusion, we recommend that systemic MDM2 expression analysis be performed in cases of retroperitoneal sarcoma. Overdependence on the expression of myogenic markers could lead to misdiagnosis in distinguishing LMS from DDLS.

Contribution of the Hair Follicular Pathway to Total Skin Permeation of Topically Applied and Exposed Chemicals.

Generally, the blood and skin concentration profiles and steady-state skin concentration of topically applied or exposed chemicals can be calculated from the in vitro skin permeation profile. However, these calculation methods are particularly applicable to chemicals for which the main pathway is via the stratum corneum. If the contribution of hair follicles to the total skin permeation of chemicals can be obtained in detail, their blood and skin concentrations can be more precisely predicted. In the present study, the contribution of the hair follicle pathway to the skin permeation of topically applied or exposed chemicals was calculated from the difference between their permeability coefficients through skin with and without hair follicle plugging, using an in vitro skin permeation experiment. The obtained results reveal that the contribution of the hair follicle pathway can be predicted by using the chemicals' lipophilicity. For hydrophilic chemicals (logarithm of n-octanol/water partition coefficient (log Ko/w) < 0), a greater reduction of permeation due to hair follicle plugging was observed than for lipophilic chemicals (log Ko/w ≥ 0). In addition, the ratio of this reduction was decreased with an increase in log Ko/w. This consideration of the hair follicle pathway would be helpful to investigate the efficacy and safety of chemicals after topical application or exposure to them because skin permeation and disposition should vary among skins in different body sites due to differences in the density of hair follicles.

Molecular mechanisms of action of different concentrations of ethanol in water on ordered structures of intercellular lipids and soft keratin in the stratum corneum.

Ethanol (EtOH) is one of the bases in topically applied medicines that promote the skin permeation of drugs. Although the effects of EtOH have been attributed to structural modifications in the stratum corneum, the underlying mechanisms, especially the influence of different concentrations of EtOH, have not been examined extensively. Structural modifications in the stratum corneum of hairless mouse due to the application of EtOH/water mixture were herein investigated at the molecular level using synchrotron X-ray diffraction. The results revealed that all EtOH concentrations examined greatly modified the short lamellar structures containing the aqueous layer in intercellular lipids and the structure of keratin fibrils in corneocytes, which can take up hydrophilic compounds. However, the long lamellar and the hydrocarbon-chain packing structures were unaffected by EtOH. Changes to the short lamellar structures were not proportional to the concentration of EtOH. However, the keratin fibril structures changed gradually with increasing EtOH concentration. The X-ray diffraction experiments enabled the effects of different EtOH concentrations on the morphology of the stratum corneum to be assessed by using a number of experimental samples to avoid variations due to individual differences. The results indicated that alterations to the short lamellar structures appeared to be related to the skin permeability of drugs with the application of EtOH/water mixture, and monotonous structural changes in the keratin fibrils with an increase in EtOH concentration may contribute to this permeation as supplement. These results will be useful for the development of new drug formulations containing EtOH.

Analysis of hair follicle penetration of lidocaine and fluorescein isothiocyanate-dextran 4 kDa using hair follicle-plugging method.

OBJECTIVE: Skin appendages including hair follicles (hfs) and the stratum corneum (sc) are beginning to be recognized as important permeation pathways for the skin permeation of drugs, but their detailed role is not yet clear. To investigate the contribution of hfs to drug permeation, we conducted skin permeation tests by controlling the hf contribution with a hf-plugging method. METHOD: Lidocaine (LC) and fluorescein isothiocyanate-dextran 4 kDa (FD-4) were selected as model drugs and pig ear skin was used as model skin. RESULTS: Skin permeabilities of ionized LC and FD-4 decreased with hf-plugging, whereas no change was observed for the skin permeation of unionized LC. A fairly good correlation was found for ionized LC and FD-4 between skin permeability and the number of hfs plugged. Permeation parameters of model drugs for both skin pathways were calculated utilizing Fick's second law of diffusion. Consequently, the sc pathway could highly contribute to the permeation of unionized LC, since unionized LC shows markedly high partition to the sc. In contrast, the hf pathway could contribute to the permeation of ionized LC and FD-4, since these had high distributions to the hf pathway in spite of its very small surface area relative to whole skin surface area. CONCLUSION: The hf pathway must be important for the skin permeation of ionized compounds and hydrophilic high molecular compounds. hf-plugging is also a useful method for assessing the skin permeability of compounds through the hf pathway.