|
Advertisement |
|
|
||
 |
|
|||||
|
|||||
|
 |
||||||
|
||||||
|
||||||
|
Journal of Clinical Oncology, Vol 22, No 10 (May 15), 2004: pp. 2027-2029 © 2004 American Society of Clinical Oncology. DOI: 10.1200/JCO.2004.06.125
Soft Tissue SarcomasCASE 2. Orbital Alveolar Soft Part Sarcoma in a ChildChinese University of Hong Kong, Shatin, Hong Kong, People's Republic of China. A 4-year-old Chinese boy presented with a gradual expanding swelling in the lower lid of his right eye persisting for 8 months. The mass was firm in consistency, pulsatile, and nontender, which significantly displaced the globe upward and limited the extraocular movement in all gazes (Fig 1). The visual acuity was 20/200 in the right eye and 20/20 in the left eye. Fundus examination results were normal, revealing healthy optic discs. The computed tomography scan showed an extraconal mass measuring 3 cm in diameter arising from the inferotemporal aspect of the right orbit. The mass was intensely and homogenously enhanced after intravenous contrast injection (Fig 2). No bony erosion or globe invasion was noted. Magnetic resonance imaging showed marked homogenous contrast enhancement with small serpiginous vessels present within the lesion. Positron-emission tomography was negative, which did not suggest a malignant potential. All features were suggestive of capillary hemangioma; however, the expanding nature warranted a transcutaneous orbitotomy and excisional biopsy. At surgery, a poorly circumscribed tumor with large feeding vessels was found. Histologically, the lesion was transversed by fibrous septa and was composed of nests or clusters of large polygonal cells separated by delicate sinusoidal vascular channels. The tumor had a microscopically infiltrative border at the tumor edge, and perineural invasion was evident. The tumor cells had distinct cell borders and possessed round vesicular nuclei with prominent nucleoli and abundant amphophilic-to-eosinophilic cytoplasm. Mitotic figures were rare (Fig 3). Histochemical staining revealed cytoplasmic positivity for periodic acid-Schiff. Rarely, the cytoplasm of the tumor cells contained a few periodic acid-Schiff–positive, diastase-resistant crystalloidlike structures (Fig 3, arrow). Under the electron microscope, the lesional cells exhibited a polygonal shape with abundant amount of cytoplasm, and the cells were surrounded by basal lamina with poorly developed junctions (Fig 4). The tumor cells contained numerous mitochondria, well-developed Golgi apparatus, stacked rough endoplasmic reticulum, and small to moderate amount of glycogen. Immunohistochemically, a few scattered tumor cells were positive for smooth muscle actin and desmin. MyoD1 stain revealed diffuse nonspecific cytoplasmic positivity. Staining for cytokeratin (AE1/AE3), vimentin, S-100 protein, HMB45, HPL, PLAP, chromogranin, and alpha fetal-protein were, however, all negative. These features are typical of alveolar soft part sarcoma (ASPS). Radical surgical excision coupled with meticulous reconstruction of this orbital lesion was adopted. No local recurrence or distant metastasis was detected at 2 years' follow-up. The best-corrected visual acuity was 20/20 in both eyes, and the visual alignments were straight.
ASPS is a rare tumor for which the pathogenesis and histogenesis remains controversial.1-3 According to the literature, it only accounts for 0.5% to 1% of all soft tissue sarcomas and 5% of pediatric nonrhabdomyosarcomatous soft tissue sarcomas.3-5 It is usually encountered in adolescents and young adults between 15 and 35 years of age, with a predominance in females (female-male ratio, 2:1).2 In adults, the lower extremities are most frequently affected, whereas it is uncommon to occur before the age of 5 years. The head and neck region is the most common site. Presentation as an orbital mass is extremely unusual except in children and infants in whom the orbit and tongue are the most common sites of origin. Early metastasis is not uncommon in ASPS, and lung, bone, and brain are the predominant sites of involvement.5 The deceptive clinical features of ASPS as a painless slow-growing orbital mass with negative findings on both magnetic resonance imaging and positron-emission tomography scans pose significant challenges for diagnosis.5,6 Common differential diagnosis includes angiosarcoma, renal cell carcinoma, paraganglioma, granular cell tumor, malignant melanoma, and alveolar rhabdomyosarcoma.3 The myogenic origin is the most favorable theory, based on the ultrastructural similarity between the lattice crystals and the actin filaments, as well as the immunohistochemical positivity of some ASPSs for desmin, smooth muscle actin, myoglobulin, and MyoD1.4,7 Surgical excision is still the mainstay of therapy for localized ASPS. No adjuvant therapy has been offered in our case, as there is no consensus as to the efficacy of either chemotherapy or radiotherapy.8,9 Authors' Disclosures of Potential Conflicts of Interest The authors indicated no potential conflicts of interest.
REFERENCES
1. Grier HE: Soft tissue sarcoma: Apples, oranges, and passion fruit. J Clin Oncol 17:3695-3696, 1999 2. Ordonez NG: Alveolar soft part sarcoma: A review and update. Adv Anat Pathol 6:125-139, 1999[Medline] 3. Hunter BC, Devaney KO, Ferlito A, et al: Alveolar soft part sarcoma of the head and neck region. Ann Otol Rhinol Laryngol 107:810-814, 1998[Medline] 4. Mukai M, Iri H, Nakajima T, Hirose S, et al: Alveolar soft-part sarcoma: A review on its histogenesis and further studies based on electron microscopy, immunohistochemistry, and biochemistry. Am J Surg Pathol 7:679-989, 1983[Medline] 5. Portera CA, Patel SR, Hunt KK, et al: Alveolar soft part sarcoma: Clinical course and patterns of metastasis in 70 patients treated at a single institution. Cancer 91:585-591, 2001[CrossRef][Medline] 6. Pang LM, Roebuck DJ, Griffith JF, et al: Alveolar soft-part sarcoma: A rare soft-tissue malignancy with distinctive clinical and radiological features. Pediatr Radiol 31:196-199, 2001[Medline] 7. Coupland SE, Heimann H, Hoffmeister B, et al: Immunohistochemical examination of an orbital alveolar soft part sarcoma. Graefes Arch Clin Exp Ophthalmol 237:266-272, 1999[Medline]
8. Spunt SL, Hill DA, Motosue AM, et al: Clinical features and outcome of initially unresected nonmetastatic pediatric nonrhabdomyosarcoma soft tissue sarcoma. J Clin Oncol 20:3225-3235, 2002
9. Pratt CB, Pappo AS, Gieser P, et al: Role of adjuvant chemotherapy in the treatment of surgically resected pediatric nonrhabdomyosarcomatous soft tissue sarcomas: A Pediatric Oncology Group Study. J Clin Oncol 17:1219-1226, 1999
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
|||||||||||
|
|||||||||||
|
|
Copyright © 2004 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
|
