Rhabdomyoblastic differentiation in a leiomyosarcoma of the retroperitoneum

Leiomyosarcoma with partial rhabdomyoblastic differentiation: first case report of primary cardiac origin

BACKGROUND

Leiomyosarcoma occurring as a primary cardiac tumor has been known as an extremely rare condition. Previous studies of leiomyosarcoma with rhabdomyoblastic differentiation have conducted to those arisen from another site, and they indicated a poorer prognosis of this tumor.

CASE PRESENTATION

A 69-year-old woman was referred to our hospital for an operation concerning umbilical hernia. Subsequent imaging examinations before an operation indicated the presence of primary cardiac malignant tumor due to its atypical shape. And then, it was surgically removed. Histopathologically, tumor cells consisted of two different types: spindle and polyhedral cells. Immunohistochemically, it is interesting to note that 2.1% of spindle cells and 23.1% of polyhedral cells showed positive reactivity for myogenin. Furthermore, we performed double-immunostaining for alpha-smooth muscle actin (SMA) and myogenin. The rates of alpha-SMA and myogenin double negative, alpha-SMA single positive, myogenin single positive, and alpha-SMA and myogenin double positive in spindle cells were estimated as 69.1%, 28.8%, 1.1% and 1.0%, respectively. In contrast, the rates in polyhedral cells were estimated as 76.9%, 0.0%, 23.1%, and 0.0%, respectively.

CONCLUSION

Our immunohistochemical evaluation suggested that rhabdomyoblastic differentiation in leiomyosarcoma might be generated not only by de novo generation from mesenchymal cells. To the best of our knowledge, this is the first case of primary cardiac leiomyosarcoma with partial rhabdomyoblastic differentiation.

Recurrent high-grade leiomyosarcoma with heterologous osteosarcomatous differentiation

Leiomyosarcomas (LM) of the soft tissue comprise approximately 5-10% of all soft tissue sarcomas. Besides the classic LM, several distinctly uncommon features of the cellular and growth patterns of LM have been described. The term "dedifferentiated LM" has rarely been used in the literature to describe soft tissue LM containing areas of undifferentiated, pleomorphic appearance or detectable heterologous differentiation. We report on a case of high-grade LM with almost entire transition to an osteosarcoma, which was classified as recurrent high-grade LM with heterologous osteosarcomatous differentiation. The identification of areas with osteosarcomatous dedifferentiation in soft tissue sarcomas can be of clinical importance because of a possible change in oncologic treatment strategies.

Leiomyosarcoma of the Uterus with Focal Rhabdomyosarcomatous Differentiation

An unusual myometrial tumor was encountered in a 70-year-old female who presented with lower abdominal fullness and symptoms related to pulmonary metastases. Laparotomy revealed a uterine mass that was removed by total abdominal hysterectomy and bilateral salpingo-oophorectomy. Multiple liver metastases also were noted. Pathologic examination of the hysterectomy specimen revealed a 25-cm, well-circumscribed myometrial mass that had a firm, white-to-yellow, focally whorled, sectioned surface with focal hemorrhage and necrosis. Within the main mass was a discrete, 7-cm, soft, gelatinous, reddish-yellow nodule. The main tumor was a well-to-moderately differentiated leiomyosarcoma, whereas the gelatinous nodule was rhabdomyosarcomatous and contained rhabdomyoblasts that exhibited cytoplasmic cross striations and immunoreactivity for myoglobin. No epithelial elements were detected in the neoplasm. At the time of last follow-up, the patient was undergoing chemotherapy. This is only the second well-documented case of a hybrid leiomyosarcoma-rhabdomyosarcoma of the uterus.

Current soft-tissue sarcoma classifications

In order to analyse the impact of modern sarcoma classification criteria, pathological material from 281 extremity soft-tissue sarcomas (STS) was reviewed. The cases were originally diagnosed between 1972 and 1994, and the most frequent diagnoses then were malignant fibrous histiocytoma (MFH) (26%), liposarcoma (21%), fibrosarcoma (11%), and leiomyosarcoma (10%). After reclassification, the proportions had changed significantly, with the largest group now being leiomyosarcomas (20%), liposarcomas (17%), synovial sarcomas (14%), and sarcomas "not otherwise specified" (NOS) (11%). The original diagnosis was changed in 57% of the cases; in particular, the number of fibrosarcomas was reduced from 32 to 6, and MFHs from 72 to 2, with 22 renamed as myxofibrosarcomas; 20 (7%) were found not to be sarcomas. The main reasons for these results are the recent advances in immunohistochemistry (IHC) together with changes in nomenclature. The findings have obvious implications, in particular for retrospective research.

Leiomyosarcomas of great vessels

Sarcomas of the great vessels are rare. Altogether 400 such cases have been described in the aorta, the pulmonary artery, and inferior vena cava. The clinical symptoms are generally related to embolic phenomena, aneurysm formation, and widespread metastases, especially to bones. With improved diagnostic modalities more cases are diagnosed and treated surgically. Resection of the tumor may prolong the patient s life. In this paper authors present two cases of such rare sarcomas. In our first case a tumor has developed in the thoracic aorta with symptoms of imminent aortic dissection. The tumorous nature of the lesion was revealed only histologically, since neither the operation, nor macroscopic picture gave any clue to its tumorous nature. The second case was a male patient with a huge retroperitoneal tumor arising from the inferior vena cava, which was clinically suspected to be a carcinomaarising in the adrenal gland.

Leiomyosarcoma of the female breast

Leiomyosarcomas of the breast are rare tumors. Less than 15 such cases have been reported in the literature so far. In this paper authors describe a case of leiomyosarcoma of a female breast presenting as a firm lobulated mass, mimicking a phylloid tumor radiographically. By fine needle aspiration biopsy, on the smears discohesive malignant looking cells were conclusive to a poorly differentiated invasive ductal carcinoma of the breast. The mastectomy specimen contained a lobulated mass, microscopically showing a partly epithelioid spindle cell tumor, immunoreactive for vimentin, desmin, smooth muscle actin antibodies, and negative for epithelial markers, hormone and growth factor receptors. Axillary lymph nodes were free of tumor. A primary leiomyosarcoma of the breast was diagnosed.

Spindle cell rhabdomyosarcoma in adults. A case report and literature review

Spindle cell rhabdomyosarcoma, a recently described variant of embryonal rhabdomyosarcoma in children, carries a favorable prognosis when compared with other types of rhabdomyosarcoma. This tumor is rare in adults, and only four cases have been documented previously. The clinicopathological study of such a case occurring in the retroperitoneal space of a 53-year-old man is herein reported. The patient died of uncontrolled local recurrence and hepatic metastases seven months after diagnosis. Based on the analysis of the data of the five cases reported, including the present one, it can be stated that spindle cell rhabdomyosarcoma in adults is not associated with the favorable outcome observed in the pediatric population.

Small cell neuroendocrine carcinoma with skeletal muscle differentiation: report of three cases

Three cases of neuroendocrine carcinoma showing skeletal muscle differentiation are presented. The tumors were located in the skin and subcutaneous tissue, the urinary bladder, and the nasal cavity respectively, and were composed by two cell types admixed intimately with each other. One cell type had features identical to those seen in conventional small cell neuroendocrine carcinoma, including scanty cytoplasm, round nuclei with fine granular chromatin, immunohistochemical reactivity for neuron-specific enolase, chromogranin and cytokeratins, and electron-dense granules on ultrastructural examination. The second cell type was either plasmacytoid or elongated and straplike, with abundant eosinophilic cytoplasm and irregular nuclei with prominent nucleoli. These cells showed immunohistochemical positivity for desmin, sarcomeric actin, myoglobin, and myogenin. They also exhibited ultrastructural evidence of rhabdomyoblastic differentiation in the form of contractile filaments with abortive Z-band formation. An origin from a cell capable of dual differentiation toward neuroendocrine and rhabdomyoblastic elements is postulated for these tumors.

Human pancreatic leiomyosarcoma (PZX-7) growing as a serially transplantable xenograft in immunosuppressed mice

BACKGROUND

Several human leiomyosarcoma xenografts have been established, but pancreatic smooth muscle sarcomas have never been serially transplanted and investigated.

METHOD

Immunosuppression of CBA/CA mice was achieved by thymectomy, whole-body irradiation, and bone marrow reconstruction. Tumor fragments were subcutaneously implanted from a Grade III pancreatic leiomyosarcoma and serially passaged for more than 24 mo. The xenografted tumors were characterized by morphological, morphometrical, biochemical, and flow cytometric methods.

RESULTS

The tumor has retained its characteristic morphology and no further differentiation occurred. The mitotic counts and the amount of the connective tissue all remained constant. The calculated volume doubling time was 11.3 d. Immunohistochemically, the tumor proved to be p53-negative, but the strong expression of the bcl-2 remained as a constant feature throughout successive transplantations. The DNA index and the proliferation indices did not change significantly with the time (mean DI: 1.65, range: 1.561-1.70; mean PI: 17.9%, range: 15.3-20.7%). Lactose dehydrogenase (LDH) isoenzyme electrophoresis evidenced a retained human pattern of the tumor even after 32 mo of transplantations.

CONCLUSION

The first human pancreatic leiomyosarcoma xenograft (PZX-7) growing in immuno-suppressed mice is described and characterized.