Low-grade fibromyxoid sarcoma arising in the big toe

Low-grade fibromyxoid sarcoma (LGFMS) is a rare tumor. Reported herein is a case of LGFMS arising in the big toe. The patient was a 58-year-old man who underwent excision of the tumor. The tumor was well-demarcated. Histologically, there were proliferating spindle-shaped tumor cells arranged in a whorled growth pattern, and the stroma showed hyalinized collagen bundles and a myxoid matrix. Nuclear mitotic figures were conspicuous in part. A large rosette-like structure with hyalinized stroma was found, which is characteristic of LGFMS. The differential diagnosis included tumor occurrence in adults; tending to arise in distal extremities; and having bland fibromyxoid histological features, such as fibroma of tendon sheath, low-grade myxofibrosarcoma and acral myxoinflammatory fibroblastic sarcoma. It was not possible to detect the FUS/CREB3L2 and FUS/CREB3L1 fusion genes from the formalin-fixed and paraffin-embedded tissue, although the histological features of the present case were typical of LGFMS. LGFMS may become more common with time, and unique cases may accumulate.     

Neural crest origin of clear cell sarcoma of tendons and aponeuroses

Summary In order to clarify the histogenesis of clear cell sarcoma of tendons and aponeuroses (CCS), two cases of human and one nude mouse-transplanted CCS line were studied using an ultrastructural and enzyme cytochemical approach. Most of the tumour cells obtained from the primary and transplanted CCS demonstrated melanosomes in various stages of development within the cytoplasm, whereas no melanosomes could be identified in the metastatic CCS. However, cholinesterase and tyrosinase activities could be demonstrated not only in the melanotic primary and transplanted CCS but also in the amelanotic metastatic CCS. The results therefore support the hypothesis that CCS is a soft tissue tumour derived from the neural crest.     

Kaposi’s sarcoma following malignant mesothelioma

We report the unusual occurrence of Kaposi’s sarcoma following asbestos-related malignant mesothelioma, in a human deficiency virus (HIV)-negative Italian man. Seropositivity to human herpes virus 8 (HHV8) was documented at the time of mesothelioma diagnosis and preceded the onset of Kaposi’ sarcoma with a time lapse of 13 months. HHV8 DNA was detected by polymerase chain reaction in lesional Kaposi’s sarcoma but not within mesothelioma. By immunostaining, mesothelioma cells expressed interleukin-6 and platelet-derived growth factor, which are important for survival of Kaposi’s sarcoma cells. Besides the possibility of a casual association, we hypothesize that mesothelioma-linked factors may have contributed to the development of Kaposi’sarcoma in the presence of HHV8 infection. Received: 12 April 1999 / Accepted: 24 June 1999     

Sarcoma of follicular dendritic cells in the dorsal mediastinum

Follicular dendritic cell sarcomas (FDCSs) are very rare and usually originate in lymph nodes. We report an exceedingly rare case with localization in the dorsal mediastinum and, for the first time, provide positron emission tomography (PET) data for this tumor. This report describes the case of a 76-year-old man with a clinically aggressive tumor in the dorsal mediastinum. Computed tomography scan revealed displacement of soft tissue and lymph nodes. PET showed that the tumor had a high proliferation rate. Investigation of the successfully removed tumor mass revealed reactivity of the tumor cells for follicular dendritic cell markers and desmosomes linking adjacent tumor cells at the ultrastructural level. Marked atypia, a high mitotic rate, and areas of coagulative necrosis were found. The tumor in our case revealed the typical features and thus was classified as FDCS. In contrast to previous reports in the literature, preoperative imaging, histology, and immunohistochemistry studies indicated at least an intermediate degree of malignancy. Nevertheless, the patient made a good postoperative recovery and remained apparently disease-free 2 years later.     

Genetic and epigenetic alterations of the PTEN gene in soft tissue sarcomas

The PTEN/MMAC1 ( PTEN ) gene was identified as a tumor suppressor gene encoding a cytoplasmic protein that controls cellular processes. To investigate the potential role and the alteration of the PTEN gene in soft tissue sarcomas (STSs), we searched for homozygous deletion and promoter hypermethylation in a series of 48 STSs that was composed of malignant fibrous histiocytoma, leiomyosarcoma, malignant peripheral nerve sheath tumor, including 2 cases with a mutation that we previously reported; differential polymerase chain reaction and methylation-specific polymerase chain reaction, respectively, were used for the analyses. Furthermore, to determine whether PTEN gene alterations are involved in the down-regulation of PTEN expression, we examined the expression of PTEN protein in 38 cases in which paraffin-embedded tissues were available for immunohistochemical analysis. In addition to our previous results showing that 2 (4%) of 51 cases had a PTEN mutation, promoter methylation was recognized in 6 (13%) of 48 cases, and homozygous deletion was detected in 1 (2%) of 48 cases in the current study. Of 6 cases with promoter methylation of PTEN gene, 5 were malignant peripheral nerve sheath tumor. Decreased expression of PTEN protein was recognized in 11 (29%) of 38 STS cases. Of 9 cases with PTEN alterations (6 cases with promoter methylation, 2 with mutation, and 1 with homozygous deletion), 3 (33%) showed decreased expression of PTEN protein. Furthermore, decreased expression of the PTEN gene showed a statistically significant correlation with high MIB-1 labeling index in 38 STS cases examined ( P = .0441). In conclusion, promoter methylation and homozygous deletion of the PTEN gene were found to be relatively rare events in cases of STS, as is mutation of the gene. Of 9 cases with a PTEN alteration, 3 (33%) showed a decrease in PTEN expression, indicating that PTEN gene alterations seem to play a minor role in the inactivation of PTEN in these tumors. Furthermore, although a further detailed analysis of a larger number of cases is still necessary, the present results suggest that PTEN expression may be a useful indicator of cell proliferation in patients with STS.     

Reassessment and clinicopathological prognostic factors of malignant fibrous histiocytoma of soft parts

Recently, the category of malignant fibrous histiocytoma (MFH) has been under discussion and new entities resembling MFH have appeared. To clarify the recent situation regarding MFH, we reassessed previously diagnosed MFH cases in accordance with the most up-to-date diagnostic criteria, which included allied tumors. We carefully reassessed 428 cases that had been diagnosed in our institute during the past 28 years. Moreover, we searched for clinicopathological prognostic factors among the cases that were finally diagnosed as MFH. Among the 428 cases, 138 cases had their diagnoses changed. The revised cases included 78 leiomyosarcomas (57%; ordinary leiomyosarcoma, 45 cases; pleomorphic leiomyosarcoma, 23 cases; myxoid leiomyosarcoma, 10 cases), 12 liposarcomas (9%; pleomorphic liposarcoma, 11 cases; dedifferentiated liposarcoma, one case), seven dermatofibrosarcoma protuberans (5%), six unclassified sarcomas (4%), five primary or metastatic carcinomas (4%), four low-grade fibromyxoid sarcomas (3%), four inflammatory myofibroblastic tumors (3%), three rhabdomyosarcomas (2%), three malignant peripheral nerve sheath tumors (2%), three acral myxoinflammatory fibroblastic sarcomas (2%) and two atypical fibroxanthomas (1.5%). Among the 1974 soft tissue sarcomas registered in our institute, MFH (428 cases) had been the most common sarcoma, followed by liposarcoma, leiomyosarcoma and rhabdomyosarcoma. However, after reassessment, leiomyosarcoma proved to be the most common soft tissue sarcoma (322 cases), followed by 290 MFH, 273 liposarcomas and 202 rhabdomyosarcomas. Among these 290 cases finally diagnosed as MFH, survival data were available in 189 cases. Tumor location in the abdominal cavity, the retroperitoneum or the head and neck (P = 0.0024), tumor size of 5 cm or more (P < 0.0001), deep tumor location (P < 0.0001), high histological grade (grade 3) based on the French Federation of Cancer Centers' grading system (P = 0.0007), and high stage (stage III or IV) based on the American Joint Committee on Cancer (AJCC) staging system (P < 0.0001) were significantly worse prognostic factors by univariate analysis. In multivariate analysis, deep tumor location and high AJCC stage were independent adverse prognostic factors. We conclude that leiomyosarcoma is the most important differential diagnosis for MFH, especially pleomorphic leiomyosarcoma from storiform-pleomorphic type and myxoid leiomyosarcoma from myxoid type. Tumor depth and AJCC stage are the most important predictive prognostic factors in MFH.     

Thymic sarcomatoid carcinoma with skeletal muscle differentiation: report of two cases, one with cytogenetic analysis

AIMS: Malignant thymic tumour histologically resembling a soft tissue sarcoma is extremely rare and defined as sarcomatoid carcinoma in the recent World Health Organization (WHO) classification. We report two such cases in which the tumour cells showed a prominent rhabdomyoblastic differentiation and analyse whether these tumours retain an epithelial nature at least in part. METHODS AND RESULTS: One tumour occurred in a 51-year-old man (Case 1) and the other in a 40-year-old woman (Case 2). Microscopically, both tumours consisted essentially of two types of tumour cells: spindle and large round cells, with no apparent epithelial components. Osteosarcomatous small foci were also found in Case 2. Immunohistochemically, desmin and muscle-specific actin were positive in the majority of both types of tumour cells, whereas myogenin was predominant in the spindle cells and myoglobin in the large round cells. Some of both types of cells expressed cytokeratin with co-expression of myoglobin in the large round cells, but with no myogenin in the spindle cells. Some cytokeratin-positive spindle cells were also negative for desmin. Ultrastructural examination of a recurrent tumour in Case 2 revealed some epithelial features among the spindle cells. Cytogenetic study of the same tumour showed a complex abnormality including der(16)t(1;16)(q12;q12.1), an identical pattern previously reported in a case of thymic squamous cell carcinoma. CONCLUSIONS: The findings support the definition in the WHO classification of sarcomatoid carcinoma that includes purely sarcomatous tumour as in the present cases. Occurrence of this type of tumour may indicate a relationship between thymic epithelial cells and myoid cells and/or a potential for divergent differentiation in thymic epithelial tumours.     

Malignant tumor of humerus with features of "adamantinoma" and Ewing's sarcoma

This female patient was born in 1935 and died in 1976 with a malignant bone tumor involving the proximal humerus following multiple local recurrences, axillary lymph node metastases, and pulmonary metastases. Histologically, over the course of time, there was an increase in features of an atypical Ewing's sarcoma, at the expense of findings of a typical, extra-cranial so-called adamantinoma. In contrast to another report, our case showed neither epithelial nor endothelial features on fine structural examination, but rather primitive mesenchymal cells, as is described for Ewing's sarcomas.     

肢端黏液样炎性纤维母细胞肉瘤2例及文献复习

目的探讨肢端黏液样炎性纤维母细胞肉瘤的临床病理学特征及鉴别诊断。方法对2例发生在下肢末端的黏液样炎性纤维母细胞肉瘤进行光镜观察和免疫组化标记，并复习文献。结果2例发生在下肢末端的病程较长的渐进性肿块，术后局部复发。镜检：病变呈多结节状，边界不清；黏液样基质中见数量不等的各类炎细胞浸润，散在或灶性分布梭形、奇异形和多空泡状脂肪母细胞样3种形态的瘤细胞。免疫表型：肿瘤细胞Vim弥漫阳性，CD68和CD34灶性阳性，CK、SMA、HHF-35、S-100蛋白、CD45、CD45R0、CD15、CD30均阴性。结论此病病程较长，术后易局部复发，是一种低度恶性的肿瘤。鉴于病变黏液样基质及各类炎细胞浸润的背景较为突出，而特征性的瘤细胞稀疏，应注意与炎症性病变或具有相似组织形态的良性或恶性肿瘤鉴别。     

Identification of CD56 and CD57 by flow cytometry in Ewing’s sarcoma or primitive neuroectodermal tumor

 CD56 and CD57 are commonly considered as natural killer and neuroectodermal markers, but their expression has been identified in a wide spectrum of neoplasms including some cases of Ewing’s sarcoma (ES) and primitive neuroectodermal tumor (PNET). We report two cases of small, round blue cell tumor (SRBCT), in which flow cytometry immunophenotyping (FCI) detected strong expression of CD56 and CD57 (one case). Immunohistochemical staining with Leu-19 and Leu-7 confirmed the FI results. Although CD56 and CD57 expression is consistent with ES/PNET, it can be potentially misleading if results of FCI are interpreted in the absence of other findings. These cases suggest the utility of FCI in undifferentiated SRBCT. The literature on CD56 and CD57 expression in ES/PNET is reviewed and discussed. Received: 5 January 1998 / Accepted: 19 February 1998