Pleomorphic Rhabdomyosarcoma Research Articles

Primary pleomorphic rhabdomyosarcoma of the kidney in an adult

Sarcoma of the kidney is uncommon and represents between 1% and 3% of all malignant renal tumors. Primary rhabdomyosarcoma of the kidney in adult age is unusual, and only sporadic cases have been reported. This is a very aggressive tumor with dismal prognosis. We report a new case of pleomorphic rhabdomyosarcoma of the kidney in an adult patient.

Primary osseous rhabdomyosarcoma with focal matrix formation mimicking osteosarcoma

We present an unusual case of primary osseous pleomorphic rhabdomyosarcoma with focal matrix formation mimicking osteosarcoma. The patient was a 21-year-old man who had suffered from pain and slight enlargement of his left calf for 2 months. A plain radiograph demonstrated a large, predominantly osteolytic mass in the region of the proximal fibula with features typical of malignant primary bone tumor. On open surgical biopsy, the tumor consisted of atypical cells, some of them presenting spindle morphology. Between them, there were bands of densely hyalinized matrix with osteoid appearance, but without definite lacunae or calcifications, and an osteosarcoma was diagnosed. Consequently, the tumor was removed. The postoperative tissue presented more pleomorphic cells with some definite rhabdomyoblasts. Desmin, actin, Myf4, and MyoD1 were positive in tumor cells, and a diagnosis of rhabdomyosarcoma was eventually made. Only few cases of primary pure bone rhabdomyosarcoma have been reported. Other bone tumors with rhabdomyosarcomatous differentiation have been described: dedifferentiated chondrosarcoma, fibrosarcoma, and osteosarcoma. Our case does not meet the criteria for sclerosing rhabdomyosarcoma, as matrix formation is focal and cells are spindle-shaped and pleomorphic. However, it is a further example of a diagnostic error in connection with primary osseous tumor.

Right atrial botryoid rhabdomyosarcoma in an adult patient with recurrent pleomorphic rhabdomyosarcomas following doxorubicin therapy

We describe a case of a 37-year-old Hispanic woman who presented with a right atrial botryoid rhabdomyosarcoma 2 years after doxorubicin therapy for a recurrent pleomorphic rhabdomyosarcoma of the chest wall. Although this may be a second primary, it most likely represents a cardiac metastasis with maturation of chemotherapy-resistant tumor cells.

Rhabdomyosarcome pléomorphe paratesticulaire de l'adulte : diagnostic et prise en charge

A paratesticular pleomorphic rhabdomyosarcoma occurring in a 63-year old man is reported. Clinical signs were like any intrascrotal tumor. CT-scan and histological examination with immunohistochemical study were necessary for the diagnosis and stadification of this cancer. The patient underwent a radical inguinal orchidectomy. The patient developed a local recurrence, which was treated by radiotherapy, and subsequently developed metastases two years later, which were treated by chemotherapy.

Epithelioid Variant of Myxofibrosarcoma: Expanding the Clinicomorphologic Spectrum of Myxofibrosarcoma in a Series of 17 Cases

Myxofibrosarcoma (MFS) is one of the most common soft tissue sarcomas of elderly patients and has a predilection for the limbs. Herein, we report a previously undescribed variant of MFS showing epithelioid morphology. Seventeen cases diagnosed as epithelioid MFS were retrieved from the authors' files from among 570 cases of MFS. Hematoxylin and eosin-stained sections were reexamined and immunostains for pan-keratin (15 cases), S-100 protein (15), desmin (15), and alpha-smooth muscle actin (13) were performed. Nine patients were men and 8 were women (age range 43 to 89 y; median 63.5). Fifteen patients presented with a mass, and in 2 of these there was also pain. Duration of symptoms varied from 1 to 24 months (median 3). Tumor size ranged from 2 to 15 cm (median 6.75). In 10 cases, the tumor was located in subcutaneous tissue and in 6 cases it was subfascial. The majority of the tumors were located on the limbs (8 lower extremities and 6 upper extremities) followed by neck (1), scalp (1), and trunk (1). Follow-up was available for 14 patients (range 2 to 240 mo; median 16). Twelve patients were treated by surgery followed by chemotherapy and/or radiation (8 cases). One patient received chemotherapy after an incisional biopsy and 1 patient was treated by surgery alone. Ten patients (71.4%) developed local recurrences. Seven patients (50%) developed metastases to lungs or retroperitoneum. Five patients (35.7%) have died of disease so far. Two patients were lost to follow-up. Morphologically, 14 cases were high grade, 2 were intermediate, and 1 was low grade. Tumors were characterized by a multinodular, infiltrating growth pattern with alternation of hypercellular and hypocellular myxoid areas; the latter showed prominent curvilinear vessels. Neoplastic cells were arranged singly and in small clusters in the myxoid areas or formed sheets in the hypercellular areas, where they showed epithelioid morphology with round nuclei, vesicular chromatin, prominent nucleoli, and moderate amounts of eosinophilic cytoplasm. The epithelioid areas were generally multifocal with admixed areas of conventional MFS. Immunostains were negative for all markers studied. Differential diagnosis included carcinoma, melanoma, myoepithelial carcinoma, pleomorphic liposarcoma, and pleomorphic rhabdomyosarcoma. In conclusion, epithelioid MFS is a rare variant of MFS, accounting for <3% of MFS in consultation material. Its natural history seems more aggressive than usual high-grade MFS, with approximately 70% local recurrence and 50% metastases, even within a relatively short follow-up period.

Immunohistochemical detection of myogenin and p21 in methylcholanthrene‐induced mouse rhabdomyosarcomas

3-Methylcholanthrene (MC)-induced 10 embryonal (ERSs) and 24 pleomorphic rhabdomyosarcomas (PRSs) of the dermis in mouse were examined immunohistochemically for myogenin, p21 and proliferating cell nuclear antigen (PCNA) nuclear reactivity and myosin reactivity. ERSs had higher expression of myogenin and p21 compared with that of myosin. PRSs were divided into two groups having high (moderate or marked reactivity; HLM) and low (mild reactivity; LLM) levels of myosin expression. Expression of p21 was higher in HLM-PRSs than in LLM-PRSs. Statistically significant association was observed between myosin and p21 expression in PRSs, but not between myosin and myogenin expression. Myogenin and p21 reactivity were observed in myoblast-like cells, but rarely in multinucleated cells. In ERSs, small undifferentiated myogenic precursor cells were also positive for p21. No difference of PCNA reactivity was observed between HLM-PRSs and LLM-PRSs, although its reactivity was higher in PRSs than in ERSs. The results suggest that myogenin is related to myoblast-like cell differentiation in PRSs and that p21 plays essential roles in myotube formation and myosin expression. In ERSs, p21 may be involved in inhibition of myogenic precursor cell proliferation and differentiation.

Rhabdomyosarcomas in Adults and Children: An Update

Rhabdomyosarcomas comprise a relatively common diagnostic entity among childhood cancers and a relatively rare one among adult tumors. They may possess a variety of histologies that generally differ among age groups. These lesions appear to be separate biologic entities as well as morphologic categories, with embryonal tumors having genetic lesions related to loss of heterozygosity and aberrant parental imprinting, alveolar tumors containing genetic fusions between PAX and forkhead genes, and pleomorphic tumors showing an accumulation of genetic lesions similar to other adult high-grade sarcomas. To present guidelines for diagnosis of rhabdomyosarcoma and recent finding concerning the biology and classification of these lesions. Review of recent and older published literature and distillation of the authors' experience. Infants and young children tend to have embryonal rhabdomyosarcomas, adolescents and young adults tend to have alveolar rhabdomyosarcomas, and older adults tend to have pleomorphic rhabdomyosarcomas, although there is some overlap. Newer rare entities, including spindle cell rhabdomyosarcoma and sclerosing rhabdomyosarcoma, have been described in children and adults. Fusion-positive tumors have a distinct molecular signature with downstream activation of a number of myogenic and tumorigenic factors. Genetic testing may be successfully used for diagnosis and may guide therapy in future clinical trials. Differential diagnosis has become simpler than in previous years, because of use of myogenic factors in immunohistochemistry, but classification based solely on histologic features remains challenging.

Spindle cell rhabdomyosarcoma in adults: clinicopathological and immunohistochemical analysis of seven new cases

Rhabdomyosarcoma (RMS) is currently classified into embryonal RMS, including its botryoid and spindle cell variants, alveolar RMS, including a solid variant, and pleomorphic RMS. In children and adolescents embryonal RMS occurs in a younger age group than alveolar RMS, and pleomorphic RMS is almost always seen in older adults. Most recently rare spindle cell and sclerosing, pseudovascular RMS have been reported in adults as well. We analysed the clinicopathological and immunohistochemical features of seven new cases of spindle cell RMS arising in adult patients. Five patients were male and two were female and the age of the patients ranged from 38 to 76 years. Four neoplasms arose on the lower extremities and one case each on the forearm, the lateral aspect of the neck and the penis. Five neoplasms were completely excised, in one incompletely excised neoplasm additional chemotherapy was given, and in one patient a biopsy was done only so far. All neoplasms arose in subcutaneous and deep soft tissues with dermal involvement in one case, and the size of the neoplasms ranged from 4 to 19 cm in largest diameter. Histologically, a plump or diffuse infiltration was seen, and all neoplasms were mainly composed of cellular bands and fascicles of atypical spindle-shaped tumour cells containing enlarged and atypical nuclei associated with a variable number of rhabdomyoblasts. In addition, focal areas reminiscent of sclerosing, pseudovascular RMS were noted in three cases, and in two cases each small solid areas with pleomorphic tumour cells as well as scattered round tumour cells were present. Proliferative activity ranged from 1 to 60 mitoses in 10 high-power fields and tumour necrosis was evident in four cases. Immunohistochemically, all neoplasms tested stained variably positive for desmin, myf-4, WT1 and CD 99, whereas fast myosin was positive in only two out of seven cases. In addition, five out of seven cases tested stained focally positive for alpha-smooth muscle actin. The remaining antibodies (h-caldesmon, S-100 protein, CD 34, pancytokeratin and epithelial membrane antigen) were all negative. Follow-up information was available in five patients (range from 10 to 48 months) and revealed lung metastases in two patients who died of disease within a short period. In summary, spindle cell rhabdomyosarcoma represents a rare neoplasm in adulthood characterized clinically by a rather poor prognosis, and shows a broad morphological spectrum including most likely the sclerosing, pseudovascular variant. Immunohistochemically, tumour cells in RMS stain positively for CD 99 and WT1 as well, which is of importance in the differential diagnosis to other mesenchymal neoplasms, whereas fast myosin does not represent a reliable marker for RMS in adults.

Intraocular Rhabdomyosarcoma in the Sibling of a Patient With a Cerebellar Medulloepithelioma

A 12-year-old girl with a three-year history of right eye disease was referred to our service after enucleation of her right eye. Histology showed a pleomorphic high-grade rhabdomyosarcoma. As there was extrascleral extension, we elected to treat her with local radiotherapy and adjuvant vincristine, dactinomycin, cyclophosphamide, and adriamycin. She remains disease free 35 months from diagnosis. Notably, a younger sibling died in early childhood as a result of a cerebellar medulloepithelioma. Although there were no teratoid elements in the rhabdomyosarcoma, our patient's unusual disease course would be consistent with rhabdomyosarcomatous differentiation in a teratoid medulloepithelioma.

Cooperation of oncogenic K-ras and p53 deficiency in pleomorphic rhabdomyosarcoma development in adult mice

Human rhabdomyosarcomas (RMSs) frequently demonstrate genetic alterations in ras and p53. To investigate their possible involvement in the tumorigenesis, we generated a knock-in mouse line with oncogenic K-ras, conditionally expressed by Cre/LoxP system on a background of p53 alteration. Electroporation of Cre expression vector in skeletal muscle tissues resulted in the generation of tumor in adults with tumor incidences of 100% at 10 weeks and 40% at 15 weeks, in p53(-/-) and p53(-/+) backgrounds, respectively. The tumor histology was pleomorphic RMS with characteristic bizarre giant cells, positive for desmin and alpha-sarcomeric actin and exhibiting remarkable increase in total and phosphorylated extracellular signal-regulated protein kinase (ERK)1 and ERK2. Loss of the wild-type p53 was detected in K-rasG12V-expressed tumors of p53(-/+) mice. Early lesions 3 weeks after electroporation consisted of proliferating populations of myogenic progenitors, including stem cells positive for ScaI antigen, immature cells positive for desmin and neural cell adhesion molecule-positive myotubes. Thus, cooperation of oncogenic K-ras and p53 deficiency resulted in the development of pleomorphic RMS in adult mice, providing a useful mouse model for further detailed studies.

Primäres Rhabdomyosarkom der Lunge als seltene Differenzialdiagnose eines kleinzelligen Bronchialkarzinoms

Primary pulmonary rhabdomyosarcoma is a rare entity and the histological differential diagnosis can be difficult. We report on a 43-year old female patient, smoker (25 pack-years), in whom a large solitary brain metastasis was diagnosed and enucleated. Histological examination revealed a typical small cell carcinoma and histological examination of biopsies obtained from a tumor in the left upper lobe of the lung was compatible with a small cell carcinoma. Despite chemotherapy there was a progressive tumor growth. Bronchial biopsies again showed a small cell tumor, although immunohistochemistry proved it to be a pleomorphic rhabdomyosarcoma. Due to the progressive tumor growth with necrosis and superinfection and a lack of further metastases lobectomy of the left upper lobe was performed, complicated by postoperative pleural empyema, limiting the possibilities of adjuvant therapy. Early relapse occurred with pleural, pulmonary, chest wall and spinal metastases. Laminectomy and extirpation of the spinal metastases, local radiotherapy and chemotherapy with iphosphamide and doxorubicine led to partial remission and clinical improvement for few months only. The patient died from metastatic primary rhabdomyosarcoma of the lung. This rare tumor mimicked small cell lung cancer. Appraisal of the atypical clinical course and a close dialogue between pathologists and clinicians enabled the correct diagnosis.

Pleomorphic rhabdomyosarcoma of the uterus in a postmenopausal patient

Pure rhabdomyosarcomas occurring in the adult uterus are very rare, with poor prognosis. We present a case of a 67-year-old woman with postmenopausal vaginal bleeding caused by pleomorphic rhabdomyosarcoma of the uterus, treated with hysterectomy, bilateral salpingo-oophorectomy, pelvic/paraaortic lymphadenectomy and partial sigmoidectomy. Postoperative chemotherapy (Doxorubicin) was given according to protocol. Follow-up examinations one year after surgery revealed no abnormalities or tumor recurrence. The rarity of this histological entity makes the presented case worthy of publication.

Novel Genes Implicated in Embryonal, Alveolar, and Pleomorphic Rhabdomyosarcoma: A Cytogenetic and Molecular Analysis of Primary Tumors

Rhabdomyosarcoma, the most common pediatric soft tissue sarcoma, likely results from deregulation of the skeletal myogenesis program. Although associations between PAX3, PAX7, FOXO1A, and RMS tumorigenesis are well recognized, the entire spectrum of genetic factors underlying RMS development and progression is unclear. Using a combined approach of spectral karyotyping, array-based comparative genomic hybridization (CGH), and expression analysis, we examined 10 primary RMS tumors, including embryonal, alveolar, and the rare adult pleomorphic variant, to explore the involvement of different genes and genetic pathways in RMS tumorigenesis. A complete karyotype established for each tumor revealed a high aneuploidy level, mostly tetraploidy, with double minutes and additional structural aberrations. Quantitative expression analysis detected the overexpression of the AURK4 gene in all tumors tested, suggesting a role for this mitotic regulator in the aneuploidy and chromosomal instability observed in RMS. Array-based CGH analysis in primary RMS tumors detected copy number changes of genes involved in multiple genetic pathways, including transcription factors such as MYC-related gene from lung cancer and the cytoskeleton and cell adhesion-encoding genes laminin γ-2 and p21-activated kinase-1. Our data suggest the involvement of genes encoding cell adhesion, cytoskeletal signaling, and transcriptional and cell cycle components in RMS tumorigenesis.

Calretinin expression in tumors of adipose tissue

Although well established as a marker of mesothelial cells, calretinin is also expressed in several other tissue types, including adipose tissue. Accordingly, immunohistochemical staining for calretinin has been described in an increasing number of neoplasms other than mesothelioma. A detailed analysis of calretinin expression in lipogenic tumors has not yet been reported, however. Given the known expression patterns of calretinin in normal tissues, we predicted that calretinin immunoreactivity would be detected in lipoma and the various histologic subtypes of liposarcoma, and that this marker might be of use in the differential diagnosis of selected fatty tumors. A variety of pleomorphic and small round cell sarcomas were studied for comparison. Calretinin immunoreactivity was detected, at least focally, in all 10 samples of normal adipose tissue and in 22 of 23 lipomas or lipoma variants. Staining for calretinin was also positive within the lipogenic component of 28 of 29 liposarcoma variants. Of the 7 dedifferentiated liposarcomas, 3 were focally positive for calretinin. Pleomorphic variants of other sarcomas, including undifferentiated high-grade pleomorphic sarcoma, rhabdomyosarcoma, leiomyosarcoma, and malignant peripheral nerve sheath tumor also exhibited focal calretinin immunoreactivity in a minority of cases, as did some small round cell sarcomas. These results suggest that calretinin immunoreactivity in normal and neoplastic adipose tissue is more ubiquitous than previously reported and may be a useful, albeit nonspecific marker of lipogenic differentiation. However, its utility in the differential diagnosis of fatty tumors appears limited.

Immunohistochemical Analysis for Mdm2 and p53 Proteins in Methylcholanthrene-Induced Mouse Rhabdomyosarcomas

3-methylcholanthrene (MC)-induced mouse 10 embryonal (ERSs) and 24 pleomorphic rhabdomyosarcomas (PRSs) of the dermis were examined immunohistochemically for nuclear reactivity of Mdm2, p53, and proliferating cell nuclear antigen (PCNA). ERSs were microscopically present in the rhabdium layer of the dermis from 10 to 13 weeks post injection (PI), and PRSs developed from 13 weeks PI. Moderate to marked Mdm2 reactivity was observed in each of the 10 ERSs, and 23 of the 24 PRSs. Moderate to marked p53 reactivity was observed in 5 of the 10 ERSs, and 19 of the 24 PRSs. p53 reactivity increased in PRSs compared with ERSs. The level of Mdm2 expression was significantly higher compared with p53 expression. Discordant Mdm2 overexpression was observed in 5 ERSs and 5 PRSs, and discordant p53 overexpression was observed in 1 PRSs, although co-overexpression of Mdm2 and p53 was observed in 5 ERSs and 18 PRSs. PCNA reactivity significantly increased in PRSs compared with ERSs. These results suggest that Mdm2 overexpression is an important pathogenic event in MC-induced mouse rhabdomyosarcomas, and its expression may be induced by p53-independent pathway.

Metastatic germ cell tumor of the lung masquerading as primary rhabdomyosarcoma

Two years after testicular resection was carried out in a 40-year-old man that revealed mixed germ cell tumor of more than one histological type (seminoma, embryonal cell carcinoma, and yolk sac tumor), he presented with an asymptomatic pulmonary nodule in his left lower lobe. Video-assisted thoracoscopic partial resection of the tumor revealed a 24 x 20 mm teratoma with somatic-type malignancy in which pleomorphic rhabdomyosarcoma was a major element. One year later, asymptomatic tumor recurrence occurred at both edges of the stapler line as 22 x 20 mm and 10 x 5 mm nodules composed only of pleomorphic rhabdomyosarcoma. Throughout the course there was no abdominal lymph node swelling detected by computed tomography (CT) and tumor markers were normal. Adjuvant chemotherapy was started after the tumor recurrence. Currently, the patient is still undergoing chemotherapy 5 months after the tumor recurrence. In conclusion, despite the fact that primary pulmonary rhabdromyosarcoma is a rare neoplasm, metastatic pulmonary germ cell tumor with somatic-type malignancy showing predominantly rhabdomyosarcomatous differentiation should be considered in the differential diagnosis of such lesions of the lung.

Primäres Rhabdomyosarkom der Lunge als seltene Differenzialdiagnose eines kleinzelligen Bronchialkarzinoms

Primary pulmonary rhabdomyosarcoma is a rare entity and the histological differential diagnosis can be difficult. We report on a 43-year old female patient, smoker (25 pack-years), in whom a large solitary brain metastasis was diagnosed and enucleated. Histological examination revealed a typical small cell carcinoma and histological examination of biopsies obtained from a tumor in the left upper lobe of the lung was compatible with a small cell carcinoma. Despite chemotherapy there was a progressive tumor growth. Bronchial biopsies again showed a small cell tumor, although immunohistochemistry proved it to be a pleomorphic rhabdomyosarcoma. Due to the progressive tumor growth with necrosis and superinfection and a lack of further metastases lobectomy of the left upper lobe was performed, complicated by postoperative pleural empyema, limiting the possibilities of adjuvant therapy. Early relapse occurred with pleural, pulmonary, chest wall and spinal metastases. Laminectomy and extirpation of the spinal metastases, local radiotherapy and chemotherapy with iphosphamide and doxorubicine led to partial remission and clinical improvement for few months only. The patient died from metastatic primary rhabdomyosarcoma of the lung. This rare tumor mimicked small cell lung cancer. Appraisal of the atypical clinical course and a close dialogue between pathologists and clinicians enabled the correct diagnosis.

Buttock sarcoma: a case report and treatment with buttockectomy

Buttock soft-tissue sarcomas are common entities that have been infrequently reported. Little is known about the epidemiology of soft-tissue sarcomas. The current therapeutic approach suggests that a large tumour excision with clear margins and effective adjuvant therapy are needed to improve overall survival rates. Overall survival rates vary between 25% and 40% for a period of 5 years and 48.5% for a 2-year period. A case is reported of a patient with a diagnosis of pleomorphic rhabdomyosarcoma on whom a buttockectomy was performed. A brief retrospective analysis of sarcomas in our centre is reported.

A retroperitoneal mass in an elderly woman. Pleomorphic rhabdomyosarcoma, classic variant, with reactive osteoclast-like giant cells.

A retroperitoneal mass in an elderly woman. Pleomorphic rhabdomyosarcoma, classic variant, with reactive osteoclast-like giant cells.

Adult paravertebral pleomorphic rhabdomyosarcoma infiltrating diffusely the whole spinal axis

The authors report a unique case of diffuse spinal metastatic disease due to a pleomorphic rhabdomyosarcoma (RMS) in an adult. In addition to its overall rarity, peculiar characteristics of the particular tumor included its site of origin, demonstrated radiologically as the lumbar paravertebral musculature (psoas muscle) and the transcanalicular spread into the vertebral canal, resulting in thecal compression at multiple levels. The salient clinicopathological characteristics of RMS, as they related particularly to the spine, are subsequently discussed and a short review of the major therapeutic modalities for these tumors is offered.