Spindle cell rhabdomyosarcoma: histologic variant of embryonal rhabdomyosarcoma with association to favorable prognosis

Congenital spindle cell rhabdomyosarcoma

Spindle cell and sclerosing rhabdomyosarcoma (ssRMS) is a rare variant of rhabdomyosarcoma, which includes three distinct subtypes. In infants, these tumors are commonly associated with recurring fusions involving VGLL2 or NCOA2 and have a favorable prognosis. We present four cases of ssRMS and 16 additional cases from the literature, which show that these patients present with localized disease and have an excellent prognosis regardless of surgical margin or lack of radiation therapy. Molecularly defined spindle cell rhabdomyosarcoma in infants is likely a biologically distinct entity which may not require the aggressive multimodal treatment used for other subtypes of rhabdomyosarcoma.

Fibroblastic and myofibroblastic tumors of children: new genetic entities and new ancillary testing

Fibroblastic and myofibroblastic tumors comprise a morphologically diverse and biologically variable group of neoplasms that affect a wide age range. Specific entities tend to occur most frequently in infants and young children. Recent years have witnessed a proliferation of information concerning the unique biology of these tumors. In this report, I will review recent findings that serve to further characterize this group of neoplasms. Included will be newer information on fibrous hamartoma of infancy, infantile myofibromatosis, lipofibromatosis, and infantile fibrosarcoma and tumors resembling it, including primitive myxoid mesenchymal tumor of infancy and new genetic entities. I will also discuss the differential diagnosis, which includes spindle cell rhabdomyosarcoma, dermatofibrosarcoma protuberans, and calcifying aponeurotic fibroma.

Undifferentiated Embryonal Sarcoma of Liver

Undifferentiated embryonal sarcoma of the liver (UESL) is a rare malignant hepatic tumor. A 47 year old male presented with symptoms of sour taste in his mouth, occasional nausea, indigestion and 15-pound weight loss over two months. He had an unremarkable upper gastrointestinal endoscopy. Imaging showed a large liver mass in the left hepatic lobe that was resected and then reported as UESL. He went on to develop lung metastases and was initially treated with doxorubicin and ifosfamide followed by switching of therapy to gemcitabine and docetaxel due to progression of disease. He had a good response after two cycles and went on to receive four more cycles, achieving stable disease. We can therefore conclude that the combination of gemcitabine and docetaxel is a potential therapeutic option for patients with UESL.

Adult paratesticular rhabdomyosarcoma presenting as acute intestinal obstruction-a case report

Paratesticular rhabdomyosarcoma is a rare intrascrotal tumor localized in the tunica vaginalis, epididymis, or spermatic cord. We report one such case in a 19-year-old man presenting with painless scrotal mass and features of acute intestinal obstruction. On exploratory laparotomy, a small nodule in sigmoid mesentery was found to be the cause of obstruction. The nodule was excised and orchidectomy was performed. Histopathological examination of both the specimens revealed features of embryonal rhabdomyosarcoma. The patient was treated with chemotherapy but died after 3 months.

Immunohistochemistry in diagnosis of soft tissue tumours

Immunohistochemistry in soft tissue tumours, and especially sarcomas, is used to identify differentiation in the neoplastic cells. In some cases, specific antigens are expressed; however, an initial panel of antibodies is often required in order to establish the broad lineage, with a subsequent, more focused, panel to allow classification. Immunohistochemical evaluation must be employed with the clinical picture, the morphology, and, when necessary, other ancillary techniques such as molecular genetics and cytogenetics. Whereas some diagnoses are evident on morphology, many soft tissue neoplasms are seen microscopically as spindle cell, epithelioid cell, small round cell or pleomorphic tumours that need to be further characterized. This article reviews selected applications of immunohistochemistry in the diagnosis of each of the principal morphological groups, concentrating on areas of most use in daily practice.

Undifferentiated liver embryonal sarcoma in adults: A report of four cases and literature review

AIM: To evaluate the undifferentiated embryonal sarcoma of liver (UESL) in adults in order to improve its diagnosis and treatment.

METHODS: Four primary and one recurrent cases of UESL were clinicopathologically evaluated and immunohistochemically investigated with a panel of antibodies using the EnVision+ system. Relevant literature about UESL in adults was reviewed.

RESULTS: Three males and one female were enrolled in this study. Their chief complaints were abdominal pain, weight loss, or fever. Laboratory tests, imaging and pathological features of UESL in adults were similar to those in children. Immunohistochemistry showed evidence of widely divergent differentiation into mesenchymal and epithelial phenotypes. The survival time of patients who underwent complete tumor resection followed by adjuvant transcatheter arterial chemoembolization (TACE) was significantly longer than that of those who underwent surgical treatment alone.

CONCLUSION: UESL in adults may undergo pluripotential differentiation and its diagnosis should be made based on its morphological and immunohistochemical features. Complete tumor resection after adjuvant TACE may improve the survival time of such patients.

Pleomorphic rhabdomyosarcoma showing smooth-muscle and fibrohistiocytic differentiation: a single case report

Rhabdomyosarcoma has traditionally been subclassified into alveolar, embryonal, and pleomorphic variants. Less commonly, spindle-cell, neuroendocrine, sclerosing, and lipid-rich or clear-cell subtypes are seen. The author recently encountered a myogenic sarcoma, with all the common markers of rhabdomyosarcoma, but expressing the unusual features of alpha-smooth-muscle actin and abundant rough endoplasmic reticulum (rER). This myogenic sarcoma, therefore, exhibited four lines of differentiation, and is documented here. The patient was a 65-year-old man with an inguinal soft tissue mass. Following surgical excision, the patient was given radiotherapy and was well without disease after 6 years. The tumor was positive for vimentin, desmin, alpha-smooth-muscle actin, alpha-sarcomeric actin, myogenin, MyoD1, and CD68. Cytoplasm was dominated by abundant rER intermingled with lipid droplets and lysosomes. Cell surfaces exhibited microvillous processes and focal adhesions, but no lamina. Subplasmalemmal smooth-muscle-type myofilaments with focal densities and rare sarcomeric filaments were seen. The low level of expression of some markers was interpreted as consistent with a poorly differentiated tumor. Given the four lines of differentiation--striated muscle, smooth muscle, fibroblastic, and histiocytic--a name reflecting its phenotype would be pleomorphic rhabdomyosarcoma showing smooth-muscle and fibrohistiocytic differentiation.

Primary and recurrent embryonal sarcoma of the liver: clinicopathological and immunohistochemical analysis

AIMS

To evaluate primary and recurrent embryonal sarcoma of the liver and to improve recognition of its morphological variants and immunohistochemical features.

METHODS AND RESULTS

Fourteen primary and two recurrent cases of hepatic embryonal sarcoma were evaluated histologically and investigated immunohistochemically with a panel of antibodies using the EnVision+ system. They were usually single, large, globular masses with solid and cystic gelatinous areas. Microscopic features included spindle, oval, stellate, epithelioid or multinucleated cells loosely or densely arranged in a myxomatous matrix. Entrapped bile ducts and hepatic cords were often present at the periphery of the tumours. Intracellular and extracellular periodic acid-Schiff-positive, diastase-resistant hyaline globules were commonly present. Recurrent tumours showed greater cellularity, anaplasia and pluripotential differentiation compared with the primary tumour. Immunohistochemistry showed evidence of widely divergent differentiation into mesenchymal and epithelial phenotypes.

CONCLUSIONS

Embryonal sarcoma of the liver may undergo pluripotential differentiation and diagnosis should be based mainly on morphological features. Immunohistochemistry has no specific or diagnostic relevance, but, by using a panel of antibodies, may help to exclude other tumours.

Cutaneous mesenchymal hamartoma with mixed myogenous differentiation

A 3-month-old infant girl presented with a polypoid lesion in the perianal region. No changes in this lesion had been noted since birth. Microscopic examination of the excised specimen showed a mixture of mesenchymal elements, dominated by haphazard thin fascicles of skeletal muscle. Collagen and vascular changes were also apparent. Immunohistochemistry showed positive staining for muscle-specific actin and desmin in the fascicular components of the lesion, and smooth muscle actin, desmin, and h-caldesmon positivity in a haphazard collection of muscle fibers in the deep dermis and anal submucosa. Numerous Verhoeff-van Gieson positive elastic fibers were also noted. Hamartomas containing skeletal muscle have rarely been reported outside of the head and neck region. They must be distinguished from a variety of other tumors, including juvenile rhabdomyoma, benign Triton tumor, and rhabdomyosarcoma.

Spindle cell rhabdomyosarcoma of the tongue in an infant: a case report with emphasis on differential diagnosis of childhood spindle cell lesions

Malignant tumors are extremely uncommon in infants, specifically in the head and neck region. We present a three-day-old infant with a large, polypoid, soft tissue mass arising from the floor of the mouth. Histologically, this neoplasm consisted of hypercellular and myxoid areas. A mixture of poorly oriented, small, undifferentiated, hyperchromatic, and round to elongate spindle cells was seen. A high degree of striated muscle differentiation was present, along with areas marked by a herringbone pattern, as well as hemangiopericytic vessels and rare mitosis. Immunohistochemical examinations revealed strong nuclear staining for myogenin and diffuse cytoplasmic staining for desmin and muscle-specific actin (HHF-35). The tumor did not stain for S-100. Based on histologic results and immunostains, this lesion was diagnosed as spindle cell rhabdomyosarcoma. This type of lesion involving the tongue is rarely seen in females, neither in association with a herringbone pattern nor with hemangiopericytic vessels. Furthermore, rare benign and malignant spindle lesions, such as cellular fibromatosis, fetal rhabdomyoma, infantile hemangiopericytoma, infantile rhabdomyofibrosarcoma, and infantile fibrosarcoma, should be in the differential diagnosis and excluded.