Alveolar rhabdomyosarcoma with del(13q14)

Alveolar rhabdomyosarcoma with unusual cytogenetic findings: one more case and review of the literature

Alveolar rhabdomyosarcoma (ARMS), a histological subtype of rhabdomyosarcoma (RMS), is characterized by an unfavorable clinical outcome. In most ARMS cases, an indicative chromosomal alteration is identified. The recurrent translocation of FKHR with either PAX3 or PAX7 genes results in the encoding of chimeric transcription factors that boost tumorigenesis. Besides structural mutations, the copy number of these genes also contributes to the oncogenic activity. In our case, a 12-year-old female patient was diagnosed with a 4 cm pelvic mass. Histopathological examination indicated an alveolar type of RMS. Subsequent FISH analysis with a dual color break-apart probe identified positive signals of FKHR3 gene break, as well as the rare event of a synchronous aneuploidy and gene deletion of FKHR. Our findings lead to the conclusion that a systematic break-apart probe FKHR FISH analysis in ARMS, confirms the diagnosis and elucidates the full spectrum of genomic alterations of this malignancy.

Vincristine, irinotecan, and temozolomide for treatment of relapsed alveolar rhabdomyosarcoma

Event-free survival for recurrent alveolar rhabdomyosarcoma (ARMS) is poor, and a consensus approach to treatment in the relapse setting has not been established. Recent studies suggest that a combination regimen of vincristine, irinotecan, and temozolomide (VITA) is active against recurrent sarcomas. We present our single-institution experience with this regimen for relapsed ARMS in heavily pretreated patients, including those with prior exposure to a combination regimen of vincristine and irinotecan. We observed a complete radiographic response in 1 of 4 patients who received VITA as a fifth attempted salvage regimen. Radiographic remission for the responsive patient was sustained for 27 weeks before disease recurrence. All therapies were administered in the outpatient setting and no grade III or grade IV toxicities were observed. These findings suggest that for patients with refractory ARMS, VITA in combination should be among the treatment options considered. They also reinforce the need for biological correlates to prospectively identify patients who may benefit from this treatment.

Malignancy after retinoblastoma: secondary cancer or recurrence?

The risk of second malignancy after retinoblastoma is reported to be as high as 20% at 10 years after initial diagnosis. This incidence may be an overestimate because of difficulties in distinguishing a second malignancy from recurrent tumor. We encountered a patient with bilateral retinoblastoma who developed a temporal mass 3.5 years after initial treatment for what had first been diagnosed as rhabdomyosarcoma; further study suggested that it was recurrent retinoblastoma manifesting as primitive neuroectodermal tumor (PNET) with multilineage differentiation. Chromosome 13 abnormalities were compatible with either rhabdomyosarcoma or recurrent retinoblastoma. To determine how often second malignancies in retinoblastoma patients may be confused with recurrent primary tumor, we reviewed our experience at Children's Hospital of Pittsburgh. Of 43 retinoblastoma patients seen between 1951 and 1992, presumed second malignancies were documented in four, including the current case. Of the three other second tumors, one had both neural and skeletal muscle differentiation; another was diagnosed as rhabdomyosarcoma unclassifiable as embryonal or alveolar; the last was an osteosarcoma. Only the osteosarcoma was clearly a second neoplasm; two and perhaps three of the other cases may be recurrent retinoblastoma. The distinction between second malignancy and recurrent retinoblastoma may be difficult but is worth determining, because treatment may differ, depending on the correct designation.

Cytogenetics of tumors of soft tissue and bone. Implication for pathology

Pathologists should be aware of the existence of diagnostically useful chromosomal rearrangements in several soft tissue and bone tumors. They include rearrangement of 8q12 in lipoblastomas, ring chromosomes in atypical lipomas, ring and giant marker chromosomes in well differentiated liposarcomas, t(12;16)(q13;p11) in myxoid liposarcomas, rearrangement of 7p21-22 in low-grade endometrial stromal sarcomas, t(2;13)(q37;q14) in alveolar rhabdomyosarcomas, t(X;18)(p11.2;q11.2) in synovial sarcomas, t(12;22) (q13;q13) in clear cell sarcomas, t(11;22)(q24;q12) in Ewing's sarcomas and peripheral neuroepitheliomas, and t(9;22)(q21-31;q11-12) in extraskeletal myxoid chondrosarcomas.

Embryonal rhabdomyosarcoma with 92,XXYY, +dmin and evidence of spontaneous cell fusion

The results of a cytogenetic analysis in an embryonal rhabdomyosarcoma are presented. A tetraploid karyotype with double minute chromosomes (dmin) was identified using a direct method of tumor tissue treatment. In 5% of the examined cells, evidence of spontaneous cell fusion was observed.

Infantile rhabdomyofibrosarcoma: a high-grade sarcoma distinguishable from infantile fibrosarcoma and rhabdomyosarcoma

Three patients with a predominantly fibrosarcomatous, desmoplastic, and fascicular spindle-cell sarcoma, resembling that of infantile fibrosarcoma but with ultrastructural and immunocytochemical evidence of rhabdomyoblastic differentiation, are described. The tumors were compared light and electron microscopically and immunocytochemically with six classical cases of infantile fibrosarcoma of the desmoplastic type. The three tumors occurred in two girls and one boy who were between 1 and 3 years of age. Ultrastructurally, the tumor cells primarily demonstrated fibroblastic and myofibroblastic features, but there were also tumor cells with sarcomere-like structures. The spindle-shaped, fibroblast-like tumor cells expressed vimentin, desmin, and smooth muscle-specific and sarcomere-specific actins. In one tumor peculiar intracytoplasmic inclusions were observed by light and electron microscopy. The immunocytochemical analysis indicated that these bodies contained all types of thin and intermediate filaments. In short-term cell cultures the tumor cells of two examined tumors revealed immunoreactivity for vimentin, smooth muscle-specific actin, and desmin. Cytogenetically, both tumors displayed a similar chromosomal pattern. One tumor contained two abnormal clones with monosomy 19 and monosomy 22, respectively, and the other tumor revealed a single clone with monosomy 19. In addition, both tumors contained clones with a normal karyotype. Two of the patients with metastatic spread died within 2 years of the primary operation. The third patient is alive with a local recurrence. The three tumors described here deviate from infantile fibrosarcoma in terms of their clinical, ultrastructural, immunocytochemical, and cytogenetic characteristics. The descriptive term "infantile rhabdomyofibrosarcoma" is suggested. The present investigation calls for detailed studies of tumors diagnosed as infantile fibrosarcomas that have metastasized and followed a fatal course.