Chest wall tumors in infancy and childhood

Mesenchymal hamartoma of the chest wall in a 10-year-old girl mimicking malignancy: a case report

We herein report a rare case of mesenchymal hamartoma of the chest wall in a 10-year-old girl. She complained of chest pain and was diagnosed with a large chest wall tumor originating from the left fourth rib. Malignancy such as osteosarcoma or chondrosarcoma could not be ruled out with imaging studies. Therefore, we performed a core needle biopsy assisted by thoracoscopy, which revealed no malignancy. Therefore, extended resection with chest wall reconstruction was unnecessary, and thoracoscopy-assisted tumor excision with only the removal of the involved fourth rib was performed without chest wall reconstruction. The postoperative course was satisfactory with no thoracic deformity and no recurrence.

Peripheral Primitive Neuroectodermal Tumor (Ppnet) of Pelvic Origin: Report of a Case Arising from an Unusual Location

A peripheral primitive neuroectodermal tumor arising from the abdominopelvic cavity is reported in a 24-year-old young male without any previous remarkable pathology. He was admitted to our hospital with complaints of urinary symptoms (acute urinary retention) and mild intestinal occlusion that had been present for three months. Physical examination and CT scan revealed a pelvic mass occupying the entire pelvic cavity. The diagnostic workup included a CT-guided biopsy which defined the tumor as a sarcomatous type. Radical surgery was performed including tumor resection, pelvic exenteration (bladder and prostate gland) and urinary and fecal diversion. Adjuvant chemotherapy (VAIA) was delivered once the histology was confirmed. We reviewed the available literature focusing on the varied nomenclature of this tumor (peripheral neuroepithelioma, Askin's tumor, Ewing's extraosseous tumor, peripheral adult neuroblastoma, peripheral primitive extracranial neuroectodermal tumor (PPNET), the clinical features, the role of diagnostic imaging techniques, pathologic assessment and controversial therapeutic management. In addition, the prognosis and survival of this rare condition were analyzed.

Surgical Approach to Primary Tumors of the Chest Wall in Children and Adolescents: 30 Years of Mono-Institutional Experience

Aims and background

Chest wall reconstruction after surgical resection for malignancies in children is a challenge for surgeons because of growth-related complications. The aim of this study is to analyze the surgical treatment and outcomes of 30 pediatric and adolescent patients treated at Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy, over a 30-year period.

Methods

Pediatric patients undergoing chest wall resection were retrospectively reviewed and selected for malignant primary tumor. Endpoints were survival, recurrences, and long-term results. We also reported the use of the innovative rib-like technique in 2 young patients.

Results

Twenty-one patients were male. Median age was 13.7 years. Eleven patients (37%) presented with a chest wall mass. Twenty-six (87%) had Ewing sarcoma family tumors. Twenty-eight (94%) received neoadjuvant chemotherapy after histologic diagnosis. One rib was resected in 13 cases; 2 or 3 contiguous ribs in 8 cases. No postoperative mortality was observed and the complication rate was 40%. Overall survival was 85.2% (95% confidence interval [CI] 65.2%-94.2%) at 5 and 10 years. Relapse occurred in 7 patients. The 5-year disease-free survival rate was 82% (95% CI 62%-92%).

Conclusions

Long-term survival is achievable for chest wall tumors in a high-volume referral center where a multimodal treatment should be set to reach the best result. As advances in medical treatment have increased survival, surgical techniques must ensure a lasting functional result. When refining the reconstruction techniques, such as the rib-like approach, it is necessary to expand the options of curative surgery for young patients.

Chest wall tumors in childhood and adolescence

Chest wall tumors in childhood and adolescence can be very heterogeneous and may appear at any age from infancy to late adolescence. They can be benign or malignant and secondary or primary. A careful history and physical examination should be followed by adequate imaging studies to delineate the primary tumor and identify possible sites of dissemination. Diagnosis usually requires either a needle or open biopsy which minimizes dissection so that a complete resection can be done later. Most neoplastic lesions require a complete resection, whereas secondary and infectious processes are treated with chemotherapy or antibiotics. Rigid chest wall re-construction has the advantage of eliminating paradoxical respiration and obviating the need for postoperative ventilation. Another advantage is maintenance of chest wall contour.

Askin tumor with metastasis to the scalp: a histochemical, immunohistochemical and ultrastructural study

A 29-year-old woman presented with facial edema, and imaging disclosed a tumor extending from the anterior chest wall to the anterosuperior aspect of the mediastinum. Transbronchial cytology of the primary tumor and biopsy of the metastatic scalp lesion were performed. Histologically, the tumor consisted of closely packed small round cells. The neoplastic cells generally had round nuclei, finely dispersed chromatin, and small to prominent nucleoli. Histochemically, the cytoplasm of the neoplastic cells contained abundant glycogen and stained with Grimelius silver. Immunohistochemically, the neoplastic cell membranes reacted with CD99 (MIC2) and the neoplastic nuclei reacted with Fli-1, but various other markers, including lymphocyte and skeletal muscle markers, were not detected. No neoplastic cells were also reactive for chromogranin A, synaptophysin, and neurofilament. Ultrastructurally, some neoplastic cells had delicate cytoplasmic processes and contained membrane-bound dense core granules in the cytoplasm. Even if results are immunohistochemically negative for neuroendocrine markers, the combination of immunohistochemistry of CD99 (MIC2) and Fil-1 may be useful in diagnosing Askin tumor or its metastatic lesion.

Predictors of outcome in children and adolescents with rhabdomyosarcoma of the trunk--the St Jude Children's Research Hospital experience

PURPOSE

The aim of this study was to determine predictors of outcome in childhood truncal rhabdomyosarcoma.

METHODS

Retrospective chart review evaluating the impact of demographic features, disease characteristics, and the extent and timing of surgical intervention on outcome was performed.

RESULTS

Thirty-three patients with a median age of 8 years were identified. Most had advanced Intergroup Rhabdomyosarcoma Study group III (n = 13) or group IV (n = 9) disease. Primary site included 20 (61%) chest wall, 6 (21%) paraspinal, 5 (15%) periscapular, and 1 (3%) abdominal wall. Most tumors were embryonal (n = 21), larger than 5 cm (n = 27), and locally invasive (n = 13); 7 had positive nodes. Tumor size, nodal status, and gross total tumor resection (upfront or delayed) were significant predictors of event-free and overall survival. Tumors 5 cm or smaller were amenable to upfront surgical resection (P = .007). In patients with tumors larger than 5 cm, resection at any time was associated with a 10-year overall survival 57% +/- 13% compared with 8% +/- 5% in those who had no surgery (P = .003). Tumor recurrence was local in 44% of cases, and survival after local recurrence was rare (1 of 8).

CONCLUSION

Tumor size, nodal status, and gross total resection at any time are significant predictors of outcome in truncal rhabdomyosarcoma. Gross tumor excision should be the goal of surgical intervention in this disease.

Respiratory insufficiency in a newborn with mesenchymal hamartoma of the chest wall occupying the thoracic cavity

The authors describe a newborn patient with mesenchymal hamartoma of the chest wall associated with pulmonary hypoplasia. A massive thoracic tumor was diagnosed by prenatal ultrasonography and magnetic resonance imaging at the 28th week of gestation. She was delivered through cesarean delivery at the 36th gestational week. Respiratory distress because of pulmonary hypoplasia necessitated neonatal intensive care. The tumor extensively involved the left hemithorax including all 12 ribs and the first 10 thoracic vertebrae, resulting in marked deformity of the thorax. At 5 days of age, she underwent the incisional biopsy through a left thoracotomy. Histopathology of biopsy specimens showed multiple components of mesenchymal origin including premature cartilage, bone, and cystic lesions resembling aneurysmal bone cyst. The tumor then showed a rapid overgrowth, but subsequently exhibited a self-limited growth for months, in which her respiratory condition gradually improved to spontaneous breathing without oxygenation support. The present case advocates perinatal preparations for associated pulmonary hypoplasia and conservative management for the neoplasm in fetuses prenatally diagnosed as having this unique pathological entity.

Peripheral Primitive Neuroectodermal Tumor (PPNET) of Pelvic Origin: Report of a Case Arising from an Unusual Location

We report a rare case of a peripheral primitive neuroectodermal tumor (PPNET) originating from the left ileopsoas muscle in an adult patient with neoplastic thrombosis of the left external iliac vein, the common femoral vein and the left popliteal vein. We performed a median laparotomy with an oblique left inguinal incision to remove the neoplasm, which consisted of a large mass surrounding the iliac-psoas muscles, extending from the transverse apophysis of the spinal column to Scarpa's triangle, and passing through the lacuna musculorum. Histopathological examination revealed a primitive neuroectodermal tumor (PNET) with focal areas of necrosis, hemorrhage and vascular invasion. Immunophenotyping was positive for CD99, NSE, and focally for CK. Ultrastructural examination of the neoplastic cells showed often multiple nuclei with dense chromatin and very large nucleoli. The patient was discharged ten days after the operation. Adjuvant treatment consisted of radiotherapy at a dose of 2000 cGy in five fractions followed by six cycles of chemotherapy. The venous thrombosis was treated by anticoagulant therapy and recanalization of the occluded veins was obtained after two months of therapy. An MRI scan, carried out 12 months later, showed a local relapse, which was treated with chemotherapy and arterial chemoembolization.

Ewing's sarcoma/primitive neuroectodermal tumor of the chest wall

Ewing's sarcoma/primitive neuroectodermal tumor is the most common tumor of the chest wall in children and adolescents. It is extremely malignant with a high frequency of both metastatic spread and of local recurrence. Cure requires intensive therapy to control both distant and local disease. Surgery and high-dose radiotherapy can achieve equivalent local control; however, radiation is associated with the additional morbidities of second malignancy and a significant adverse impact on both cardiac and pulmonary function. The optimal therapeutic sequence is initial biopsy followed by induction chemotherapy with subsequent resection of the primary tumor. This approach will achieve the lowest incidence of tumor present at the margins of resection and, hence, need for postoperative radiotherapy. The chest wall is a rare site for tumors in children and adolescents. In a series reported from St Jude's Children's Research Hospital, chest wall tumors constituted only 1.8% of the solid childhood tumors. They are primarily mesenchymal in origin and the Ewing's sarcoma/primitive neuroectodermal tumors (PNET) predominate. This report concentrates on the later tumors. They are recognized to be extremely malignant, and cure in those who present with metastatic disease is very difficult to achieve. Recent advances in our understanding of their cytogenetic basis and optimal treatment are presented.

Soft-tissue sarcomas of the diaphragm: a report from the Intergroup Rhabdomyosarcoma Study Group from 1972 to 1997

PURPOSE

To describe clinical details and outcome of children and adolescents with primary sarcomas of the diaphragm treated on Intergroup Rhabdomyosarcoma Studies (IRS) I through IV.

PATIENTS AND METHODS

We reviewed the records of 15 patients with sarcoma of the diaphragm who were entered on IRS Group protocols between 1972 and 1997. Patient ages at diagnosis ranged from 0.5 to 20 years (median, 13 yrs), and 10 were girls. Patients had chest pain, dyspnea, and/or coughing, decreased breath sounds, and occasionally hepatomegaly.

RESULTS

Localized, gross residual disease after initial surgery was present in 10 patients, and five had metastases at diagnosis (pleura, 3; pericardium, 1; lungs and bones, 1). Tumor subtypes were alveolar rhabdomyosarcoma (RMS) in five cases, embryonal RMS in three, undifferentiated sarcoma in three, extraosseous Ewing sarcoma in three, and unclassified sarcoma in one. Treatment consisted of radiation therapy to the primary tumor and metastases when feasible, and combination chemotherapy with vincristine, actinomycin D, and cyclophosphamide with or without doxorubicin, ifosfamide, cisplatin, and etoposide. Ten patients achieved complete remission (67%), four obtained a partial remission, and one was improved. Five patients (33%) are continuously failure-free and alive at a median of 8.8 years from diagnosis (range, 1.1-15 yrs). However, the other 10 patients experienced relapse at 0.3 to 2 years from start of therapy (median, 1 yr). Sites of relapse were local in five, distant in three, and combined in two. Death after relapse occurred at 0.39 to 2.6 years (median, 1.6 yrs) from diagnosis.

CONCLUSIONS

Sarcomas of the diaphragm are generally deemed unresectable at diagnosis and/or are metastatic. Most of them are not embryonal rhabdomyosarcomas. Treatment with more effective primary chemotherapy to shrink the tumor, followed-up by surgical resection and radiation therapy, should improve the prognosis for patients with sarcomas arising in the diaphragm, especially for the majority who have localized tumors.

Malignant chest wall tumors in children and young adults

PURPOSE

Primary chest wall malignancies, which occur infrequently in children, can pose complex technical challenges to the surgeon. This study was undertaken to evaluate the pathology, treatment approaches, role of surgical resection and reconstruction, and outcomes of patients with these tumors.

METHODS

This is a retrospective review of all patients with malignant primary chest wall tumors treated at our institution between February 1983 and July 1998.

RESULTS

Nineteen cases were identified: malignant small round cell type (MSRCT, also called Ewing's sarcoma, primitive neuroectodermal tumor [PNET], and Askin's tumor; n = 8), rhabdomyosarcoma (RMS; n = 6), and other tumors (n = 5). Three patients underwent "upfront" complete resections. Sixteen patients underwent initial biopsy, followed by chemo- or radiotherapy. Nine of these 16 survived to undergo delayed chest wall resections. Six of the 12 "resected" patients required en bloc resection of adjacent muscles or organs; 7 required complex chest wall reconstruction. Eight of 19 patients (42%) have survived (median follow-up of survivors, 4 years), all with no evidence of disease; the remaining 11 patients died of progressive disease. Local invasion did not alter chance of survival. Two of the 10 patients with metastases at diagnosis (20%) survived. Six of the 9 patients (67%) with localized disease survived. All five patients with tumor types other than MSRCT or RMS, metastatic or not at diagnosis, are alive with no evidence of disease. There were no local recurrences.

CONCLUSION

Surgical resection, with en bloc removal of involved structures and chest wall reconstruction, provides excellent local control of malignant chest wall tumors.

[A resected case of malignant peripheral nerve sheath tumor (MPNST) necessary to distinguish from Askin tumor]

We have treated a patient with malignant peripheral nerve sheath tumor (MPNST) for 7 years by interdisciplinary therapy. The diagnosis and treatment are reported with the clinical course so far. A 20-year-old man underwent surgical resection of a tumor on the left side of the chest in 1990, and a diagnosis of Askin tumor was made. In 1993, the disease recurred in the left axilla and was surgically resected. The surgical specimen was investigated histologically, and a diagnosis of MPNST was made instead of Askin tumor. Recently, a tumor began to grow in the left pleural cavity and was surgical resected. The tumor tissue contained both cells with oval and long spindle nuclei, which were intermingled with each other. Immunohistochemically, the tumor cells were positive for vimentin and some of them were positive for S100 protein. Because electron microscopy showed cytoplasmic processes on the tumor cell and basal lamina-like structures, a diagnosis of recurrent MPNST was made. Because this lesion resembled Askin tumor in its clinical manifestations and histological characteristics, differential diagnosis from Askin tumor was necessary. When a malignant soft tissue tumor arising from the mediastinum or chest walls is detected, immunohistochemical and electron microscopic studies should be performed. The diagnosis should be based on the overall findings including the location and clinical data.

Contamination of the pleural surfaces in childhood sarcoma. Use of colloidal P-32 to reduce radiation dose to the whole lung

Children with pulmonary sarcomas who have diffuse contamination of the pleural cavity present a difficult management problem for the radiation oncologist. Doses required to control even microscopic disease exceed lung tolerance. We report on the use of intracavity colloid P-32 in an attempt to treat the pleural surface and spare normal lung parenchyma and tissues of the chest wall. Three children--18 months, 12 years, and 3 years of age--had spillage of pulmonary sarcomas into the chest cavity. All children were treated with systemic chemotherapy. Initially, 0.5 mCi of technetium sulfur colloid (99mTc-sulfur colloid) was instilled into the pleural space to ascertain even distribution of isotope. This was then followed by installation of 5.0 mCi of colloidal P-32. Uniform distribution was then confirmed by bremsstrahlung scanning. All three patients are in complete remission 3.5 years, 3 years, and 1 year after treatment, respectively. The major toxicity was asymptomatic pleural thickening, which could be confused with disease. This was confirmed histologically to be fibrous in the first patient. The process diminished or stabilized with time in all 3 patients over the period of observation. In this small series, intrapleural colloidal P-32 appeared to be safe and well tolerated and would be expected to be less toxic than wide-field external beam in the treatment of spilled pulmonary sarcomas.

Chest wall rhabdomyosarcoma

BACKGROUND

Rhabdomyosarcoma is the most common soft tissue sarcoma in the pediatric age group. The primary tumor site is an important prognostic determinant. Axial lesions are associated with decreased survival and provide a clinical challenge.

METHODS

A retrospective analysis of the authors' institutional experience between 1972 and 1996 was performed. Patients were from a data base of 302 consecutive cases.

RESULTS

Fifteen consecutive patients with chest wall rhabdomyosarcoma were identified. The median age was 16 years (range, 6 months-25 years). Median follow-up was 6.6 years (range, 10 months-18.5 years). Nine patients presented with a mass, six with pain, two with respiratory distress, and one with ulnar neuropathy. The median lesion size was 7 cm (range, 3-16 cm). A surgical procedure was the initial therapy for 13 of 15 patients. Fourteen patients received radiation therapy with a median dose of 4400 cGy. All but one were included in institutional-based trials using multiagent chemotherapy. At last follow-up, 10 patients were alive and disease free, with a median survival of 123 months (range, 51-221 months). Seven of ten survivors underwent a complete resection as their initial therapy. There was no surgical mortality, and only two patients had treatment-related complications. Of the five patients who died, two underwent complete resection as their initial therapy. All five patients had invasive tumors. Four were > 10 cm, 3 were of alveolar subtype, and 2 were embryonal.

CONCLUSIONS

Complete resection of chest wall rhabdomyosarcoma is recommended. However, survival is possible for patients with microscopically positive surgical margins with the addition of chemotherapy and radiation.

Mass on chest X-ray

Images

Malignant peripheral neuroectodermal tumors in urology

During the past few years, a new tumor type has emerged in the pediatric and adolescent group of cancer patients, which has been designated malignant peripheral neuroectodermal tumor (MPNT). This tumor has some clinical and pathological signs in common with either soft-tissue sarcomas or classic Ewing's sarcoma, but is defined as a distinct entity because of its immunohistological characteristics. The tumor expresses neuronal markers, but the pattern varies: chromogranin, neuron-specific enolase, synaptophysin, protein S-100 and others. MPNT can occur in the urogenital region. The differential diagnosis on clinical grounds must include Ewing's and soft tissue sarcomas, and also Wilms' tumor and its variants. MPNT are often wide spread in the urogenital region when first diagnosed. Response to radiotherapy and combination chemotherapy is limited. Radical surgery is not always possible. The prognosis therefore remains rather poor at this time. A selection of MPNT patients is presented to demonstrate the various problems associated with this diagnosis. MRI and CT of all patients showed large tumors with direct infiltration of the surrounding structures. MRI is the best imaging modality for diagnosis and therapy monitoring in these tumors, because of its high soft-tissue contrast.

Recurrent intrapulmonary malignant small cell tumor of the thoracopulmonary region with metastasis to the oral cavity: review of literature and case report

Malignant small cell tumor of the thoracopulmonary region (MSCT) was first described in 1979 and has been referred to as the Askin tumor. This malignant neoplasm is a member of the peripheral primitive neuroectodermal tumor (PPNET) family and typically involves the periosteum, soft tissue, and extrapulmonary tissue of the thoracic wall. MSCT may also involve the lung parenchyma by local extension or may arise de novo in peripheral lung tissue. Local recurrence, abdominal involvement by tumor extravasation across the diaphragm, and skeletal metastatic disease are relatively common. However, metastasis to the head and neck region and in particular to the oral cavity is extremely rare. We present a recurrent intrapulmonary MSCT with metastasis to the oral cavity in an adolescent Hispanic boy, and review the literature regarding this member of the PPNET family. Differentiation from neuroblastoma may be made based on immunoreactivity for beta 2 microglobulin and HBA71 and lack of immunoreactivity for chromogranin in PPNET and MSCT. Ultrastructural features commonly seen in MSCT and PPNET are round to ovoid tumor cells with occasional cytoplasmic processes with relatively few pleomorphic dense core granules. These tumors lack the gangliocytic and Schwann cell differentiation that is characteristic of neuroblastoma. MSCT and PPNET have a common reciprocal cytogenetic translocation [t(11;22)q(24;q12)], which is shared with Ewing's sarcoma. Prognosis in MSCT is quite dismal, with a 2-year survival of 38% and a 6-year survival of only 14%.

Malignant neuroectodermal tumour of the chest wall (Askin tumour): CT and MR findings in eight patients

Malignant neuroectodermal tumour of the chest wall (Askin tumour) is an uncommon malignant neoplasm affecting young adults. We retrospectively reviewed the clinical and pathological information and radiologic studies in our archives on eight cases of this tumour. All cases were pathologically proven. Plain films, CT scans and radionuclide images were available in all cases. MR images were also available in two patients. Although rare, Askin tumour should be included in the differential diagnosis when a chest wall or thoracic paraspinal mass is identified in a young individual.

Malignant small round cell tumor (Ewing's-PNET) of the chest wall in children

From 1976 to 1989 the authors treated 21 infants and children with malignant tumors of the chest wall. Fifteen were classified as Askin's tumors or Ewing's sarcoma, which we now consider as a single entity of primitive neuroectodermal origin. They are infrequent but highly aggressive tumors that involve the chest wall in children. Five patients presented with metastatic disease; despite chemotherapy and radiotherapy, all succumbed to progressive disease. Ten patients with localized disease received combined modality therapy including surgical resection (three after initial chemotherapy), radiotherapy, and chemotherapy. Surgery involved resection of the mass and up to three ribs, with prosthetic mesh reconstruction in one patient. Six of the 10 patients with localized disease are continuously disease-free 3.5 to 9 years (median, 5 years) following diagnosis. No patient had local recurrence. Of the four whose treatment failed, one died (free of disease) from complications after resection of an extensive primary tumor. In the second patient, acute monocytic leukemia developed shortly after relapse in a distant bone site. The patient died during induction for the leukemia. In the other two patients, hilar and carinal lymph node relapse occurred 68 and 80 months after initial treatment. One of the patients is considered in second remission (now 105 months later) after further chemotherapy (Adria-VAC) and radiation; the other succumbed to secondary relapse 17 months after second remission was achieved through chemotherapy, radiation, and surgery. Initial percutaneous needle biopsy of the large lesions has provided adequate material for histological, immunohistochemical, cytogenetic and ultrastructural diagnosis, and permitted initial chemotherapy before proceeding to surgical resection.(ABSTRACT TRUNCATED AT 250 WORDS)

Does malignant small round cell tumor of the thoracopulmonary region (Askin tumor) constitute a clinicopathologic entity? An analysis of 30 cases with immunohistochemical and electron-microscopic support treated at the Institute Gustave Roussy

The morphology and clinical outcome of 30 patients with malignant small round cell tumors located in the thoracopulmonary region (Askin tumor) are reported. Histologically, all tumors had similar patterns, with small round-to-oval cells and a lobulated stroma. Immunohistochemical analysis always resulted in positive staining for one or several neural markers. No significant differences were found compared with the immunomarkers in 26 typical Ewing's sarcomas located outside the thoracic wall. In three specimens, electron microscopy confirmed the presence of membrane-bound neurosecretory granules. It was confirmed that there is a remarkable similarity among all malignant small round cell tumors, including Askin tumor and Ewing's sarcoma. Overall survival was poor with a 2-year rate of 38% and a 6-year rate of 14%.

Therapy-related acute myeloid leukemia secondary to inhibitors of topoisomerase II: from the bedside to the target genes

In the past five years, several groups have reported acute myeloid leukemia (AML) often monoblastic, as a complication of chemotherapy regimens including the epipodophyllotoxins, etoposide and teniposide. This syndrome is distinct clinically, pathologically and cytogenetically from classical therapy-related myelodysplasia and AML. There is also evidence that other topoisomerase II inhibitors, such as the intercalating agents (including doxorubicin, mitoxantrone, and actinomycin D) may be leukemogenic. Furthermore, there may be further interactions from concomitant topoisomerase II inhibitors and alkylating agents. Topoisomerase II inhibitors induce DNA cleavage and other chromosomal aberrations, including sister chromatid exchanges. These clastogenic abnormalities are not fully understood, and may be specific for each cytotoxic agent. Work is in progress to clone breakpoints such as the t(9;11) and t(8;21) and the use of the resultant DNA probes will enhance our understanding of the leukemogenic process. Given the potential diversity in patients with secondary leukemia, cytogenetic studies should be mandatory for both enhancing our knowledge base and guiding treatment in individual patients. Clinicians must also be wary of the leukemogenic potential of 'dose-intense' regimens including agents such as etoposide and doxorubicin.

A case of small round cell tumor of the thoracopulmonary region with myogenic and neurogenic elements

We here report a unique case of a young boy with an intrathoracic tumor which consisted of neurogenic and myogenic elements. The initial pathological diagnosis was alveolar rhabdomyosarcoma. The tumor tissue from surgical resection was composed of three parts, each showing a different histological appearance, i.e. a monotonous small cell area, an alveolar area, and an area consisting of pleomorphic rhabdomyoblasts. The small round cells in the monotonous area were immunoreactive with the antibodies for Leu7, neuron-specific enolase (NSE), neurofilament proteins (NFP), and beta 2 microglobulin, but not with the antibody for desmin. These cells also had dense core granules. The tumor cells in the alveolar area were immunoreactive with the antibodies for Leu7 and desmin, but not with the antibody for NFP. Pleomorphic rhabdomyoblasts were immunoreactive with the antibody for desmin, but not with the antibodies for Leu7 and NFP. These findings imply that this tumor consisted of neurogenic and myogenic elements and is considered to be a special type of rhabdomyosarcoma.

Soft-tissue sarcomas other than rhabdomyosarcoma in children

Forty-seven children with nonrhabdomyosarcomatous soft-tissue sarcomas (NRSTS) were treated by the Hematology-Oncology Service at Texas Children's Hospital, Houston, Texas, between 1958 and 1990. The male:female ratio was 1:1, and the median age was 11 years (3 weeks-16 years). A preexisting condition was found in 9/47 (19%) patients including neurofibromatosis (3), Down's syndrome (1), spina bifida (1), congenital facial asymmetry (1), giant pigmented nevus (1), juvenile onset diabetes mellitus (1), and acquired immune deficiency syndrome (1). The site of primary tumor was head and neck (3), trunk (33), and extremities (11). Twenty-four patients (51%) have survived free of disease with a median follow-up of 5 years (4 months-22 years). No patient whose disease recurred achieved a second remission. Of the 19 patients with group I disease, 16 (84%) survived free of disease. Wide excision of the primary tumor, with no microscopic residual disease, was associated with the greatest chance of disease-free survival.

Extracranial primitive neuroectodermal tumors. The Memorial Sloan-Kettering Cancer Center experience

The clinical data of 54 patients (57% males) with extracranial primitive neuroectodermal tumors (PNET) seen over a 20-year period at Memorial Sloan-Kettering Cancer Center were reviewed. The age at diagnosis ranged from 1 month to 81 years (median, 17 years). One PNET arose in a previously irradiated site. One patient had an unaffected identical twin. Primary sites were thoracopulmonary (n = 25), pelvis (n = 12), retroperitoneum or abdomen (n = 10), limbs (n = 5), neck (n = 1), and unknown (n = 1). At diagnosis, epidural extension was present in 13 patients with truncal primaries, and 11 patients had distant metastases. All of the latter died with disease. Progression-free survival (PFS) among the 43 patients with localized tumors (all greater than 5 cm) was 25% at 24 months. Two of 13 patients who relapsed after more than 12 months without therapy were long-term survivors. Patients with localized PNET who had resection of all gross disease within 3 months of diagnosis had a significantly longer PFS (P = 0.0003). Radiation therapy caused tumor shrinkage but was not curative of measurable disease. A dose-response effect was evident with the most commonly used drug, cyclophosphamide. Myeloablative regimens using melphalan (n = 8) or thiotepa (n = 1) with autologous bone marrow rescue were not clearly beneficial. The treatment results favor: (1) early surgical removal, (2) dose-intensive use of drugs active against PNET (especially cyclophosphamide), and (3) radiation therapy to ablate residual microscopic disease.

The radiology of Askin tumours

The Askin tumour is a highly malignant primitive neuroectodermal tumour (PNET) of the chest wall occurring in children and young adults. We describe three cases to illustrate the clinical and radiological aspects of this tumour, which are not well documented. Patients present with a chest wall mass, pain and constitutional symptoms. Radiology demonstrates a large soft tissue chest wall mass, local rib erosion and pleural effusion. Recurrence tends to be local chest wall, pulmonary or skeletal. The prognosis is poor. Askin tumours must be considered in the differential diagnosis of chest wall masses in children and young adults.