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The authors discuss the epidemiology, pathology, clinical presentation, and treatment of rhabdomyosarcoma as well as some of the less common sarcomas of childhood and adolescence. Special focus is placed on making careful histopathologic distinction between entities and on clearly recognizing distinct clinical syndromes.
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Of the solid tumors of childhood, neuroblastoma--the prototypic small-, round-, blue-cell neoplasm--occurs in the youngest patients and has shown the least predictable biologic behavior and response to therapy. It is often confused clinically and histologically with Wilms' tumor, rhabdomyosarcoma, lymphoma, and especially, Ewing's sarcoma. Certain clinical and histologic features that may be useful in prognosis have been identified, however, and a variety of distinctive light microscopic, electron microscopic, and immunohistochemical features may be useful in differentiating this and related tumors. Many of the varied techniques useful in the differential diagnosis of these tumors can now be employed routinely in most laboratories.
A series of case presentations show unique challenges associated with childhood round cell tumors and the role of ancillary techniques in diagnosis. Electron microscopy is shown to be the most powerful individual technique. Immunohistochemistry is less effective but also essential. Other ancillary techniques may provide needed additional diagnostic information. Because this is an area where it is of great importance to secure the most rapid, accurate, and specific diagnosis possible, an integrated multimodal approach is recommended--incorporating light microscopic, electron microscopic, and immunohistochemical studies as a matter of routine, and providing for cytogenetic and/or molecular diagnostic studies as indicated.
In animal models, the importance of tumor-derived antiangiogenic factors in controlling metastases has been demonstrated by the growth acceleration of distant metastases after surgical excision of a primary tumor mass. We report the case of an infant who developed rapidly growing cutaneous metastases after surgical resection of a neoplasm of an upper extremity. The tumor was undifferentiated, with some morphological features of primitive neuroectodermal tumor. To test the possibility that the primary tumor was secreting an angiogenic inhibitor, cells from the primary tumor were grown in culture, and the culture medium was tested with an in vitro endothelial cell migration assay and Western blot. The cultured cells secreted sufficiently high levels of an angiogenic inhibitor to overcome the inducing ability of vascular endothelial growth factor and basic fibroblast growth factor. One of the secreted proteins was thrombospondin-1, a potent antiangiogenic glycoprotein. The rapid dissemination of distant metastases after resection of the primary tumor in this case suggests that tumor-derived angiogenic inhibitors are important in maintaining the local net balance of angiogenic mediators controlling the growth of micrometastasis.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Ultrasonography and cytologic examination of the vitreous aspirate established the correct pre-enucleation diagnosis of medulloepithelioma in the case of an 8-year-old boy. The use of a muscle hook allowed the examiner to elevate the eye and bring the ciliary body into adequate ultrasonographic view. Histopathologic examination of the enucleated eye showed a partially pigmented mass composed of elongated neuroepithelial tubules and cords arising from the ciliary body inferiorly. Several tubules displayed a central lumen with rosette-like structures. The tumor was classified as a benign, nonteratoid medulloepithelioma. Electron microscopically the lumens of the rosettes contained myriad, slender microvilli, and were bordered by numerous terminal bar complexes and areas displaying zonula adherens and zonula occludens type junctions. Additionally, invaginating gap junctions, which clearly established that the tumor originated from the ciliary epithelium, were identified.
A 34-month-old girl was treated for anterior uveitis, a superiorly subluxated cataract, rubeosis iridis and secondary glaucoma of the right eye of 3 months duration. She was diagnosed as having medulloepithelioma only after a mass was subsequently identified on the anterior surface of the iris. A low grade malignant nonteratoid medulloepithelioma was found to involve the ciliary surface throughout the circumference of the enucleated right globe. These tumors are generally associated with a good prognosis for survival, but are potentially lethal when they extend extrasclerally.
Esthesioneuroblastoma, a tumor that arises from the olfactory sensory epithelium, often manifests with ocular and orbital signs and symptoms. A review of 38 cases of esthesioneuroblastoma at the Mayo Clinic revealed that ophthalmic signs or symptoms occurred in 28. Twenty patients had ophthalmic signs or symptoms at the time of presentation, and five of these had ocular symptoms as the primary complaint. Five patients presented to an ophthalmologist, but a nasal or paranasal sinus tumor was not suspected. Periorbital pain and excessive tearing were the most commonly reported symptoms. The most common ophthalmic sign was eyelid edema followed by proptosis, globe injection, and ptosis. Recognition of the signs and symptoms of neoplasms of the nose and paranasal sinuses and consideration of esthesioneuroblastoma in the differential diagnosis by clinicians and pathologists allow for prompt management of this tumor.
A predominantly benign medulloepithelioma of the ciliary body was diagnosed in an 8-year-old girl and resected by iridocyclectomy. It recurred twice during 30 months. Highly malignant histopathologic features developed, and the eye finally perforated and had to be enucleated. No recurrence or metastases have subsequently developed. Histologically, the tumor was a nonteratoid medulloepithelioma consisting of elements resembling embryonic retina, nonpigmented ciliary epithelium, and neuroblasts, but had also areas of obvious glial and neuronal differentiation as judged by immunohistochemistry. The neuroepithelial tumor cells were positive for neuron-specific enolase, vimentin, and often for S-100 protein. The neuroblastic cells were generally positive for neuron-specific enolase and synaptophysin, but were intermixed with glia-like tumor cells positive for vimentin, glial fibrillary acidic protein, and S-100 protein. The results suggest that even a nonteratoid medulloepithelioma may be, unlike retinoblastoma, a truly multipotential tumor.
The left eye of an otherwise healthy child was enucleated at the age of 2 months because of an enlarging mass involving the temporal iris, ciliary body, and anterior retina. The initial histopathologic diagnosis was malignant medulloepithelioma with orbital extension. Closer study revealed a superotemporal chorioretinal and ciliary body coloboma; dysplasia of the adjacent retina; a glioneuromatous mass replacing the temporal ciliary body, chamber angle structures, and iris and extending through the sclera to involve the insertion of the lateral rectus muscle; neuroepithelial elements resembling medulloepithelioma; and abnormally developed iris pigment epithelium, and dilator and sphincter muscles. Immunohistochemistry demonstrated that the main mass consisted of neurons positive for neuron-specific enolase (NSE), synaptophysin and neurofilaments, and glial cells expressing vimentin, glial fibrillary acidic protein, and S-100 protein. The neuroepithelial elements reacted positively for cytokeratins and S-100 protein, in addition to NSE and vimentin, suggesting ciliary epithelial rather than embryonic retinal origin. The tumor was rediagnosed as glioneuroma, which in this case was part of a widespread colobomatous dysplasia of the anterior uvea and retina. The patient is alive without metastases or local recurrence 2 years following enucleation and subtotal removal of the lesion.
We compared the signal transduction pathways activated by stromal cell-derived factor-1 (CXCL12) chemokine in two different cell systems: primary cultures of rat cerebellar granule neurons (CGN) and human neuroepithelioma CHP100 cells. Both cell types express functional CXC chemokine receptor 4 (CXCR4), which is coupled both to extracellular signal-regulated kinase (ERK) and Akt phosphorylation pathways. The activation of ERK shows different dependency on the phosphatidylinositol 3-kinase (PI3-K) pathway and different sensitivity to pertussis toxin (PTX) treatment, indicative of coupling to different G proteins in the two cell systems considered. We demonstrate that the inhibition of either the ERK kinase or the PI3-K pathways blocks the CXCL12 induced-chemotaxis in CHP100 cells; while only PI3-K activity is stringently necessary for CGN migration.
The terminology, classification, and histopathologic features of teratoid and neural masses of the nasal area of children can be confusing. Definitions, clinical features, and histopathologic differential diagnoses are discussed.
Two cases of primitive neuroectodermal tumor of the lung are reported. The first case is a 41-year-old man with a tumor in the left upper lung, and the second case is a 30-year-old woman with a tumor in the right lower lung. In both cases, the tumors originated in the lung but not in the chest wall. No distant metastasis was detected. In case 1, transcutaneous fine-needle biopsy (TCNB) revealed small round cell proliferation, although bronchoscopic examination showed no abnormal findings. Both the expression of Mic2 protein and t(11;22)(q24;q12) translocation were proved in the tumor cells. The tumor cells were positive for periodic acid-Schiff (PAS), neuron-specific enolase (NSE), and vimentin, but negative for Leu7, chromogranin A, and pro-gastrin-releasing peptide (ProGRP). In case 2, bronchoscopic examination showed only compressive change in right lower lobe bronchi. TCNB revealed small round tumor cells expressing Mic2 protein. The tumor cells were negative for leukocyte common antigen, S100 protein, pankeratin, chromogranin A, and desmin, but weakly positive for NSE and moderately positive for Ki-67 (MIB1). Both patients were successfully treated by the combination of surgical resection and chemotherapy, and are alive with no sign of recurrence for approximately 22 months in case 1 and 16 months in case 2.
Primitive neuroectodermal tumor (PNET) of the orbit is rare. We present a case of a young patient with orbital PNET extending to the endo-crane and sinuses, which had been treated 10 years before with the diagnosis of rhabdomyosarcoma. The diagnosis was corrected with immunohistochemistry. Through this observation, we discuss the clinical aspects, the diagnosis difficulties, and the therapeutic options of this rare affection.