Teratoid Wilms' tumor is an unusual morphological entity characterized by a classic triphasic malignancy with predominantly heterologous tissue. The authors describe two cases of teratoid Wilms' tumor with an extrarenal site: one in a 13-year-old girl with vaginal spotting (patient 1) and another in a 1-day-old girl with a sacrococcygeal mass (patient 2). The tumors were located in the vagina and coccyx, respectively. Under the initial clinical diagnosis of sarcoma botryoides in patient 1 and teratoma in patient 2, the masses were removed. Microscopically, both tumors were composed of typical triphasic Wilms' tumor tissue with primitive cartilage and skeletal muscle, and squamous and columnar mucinous epithelia. The patient with sacrococcygeal mass (patient 2) had an elevated serum AFP level. The patients were given chemotherapy and have now remained disease free for 7 years 1 month, and 2 years 5 months after surgery, respectively. Familiarity with this rare variant of Wilms' tumor might be important in arriving at a correct diagnosis.

J Korean Neurosurg Soc 48 : [276][277][278][279][280] 2010 Liposarcomas are malignant tumors of the soft tissue, with myxoid liposarcoma being the second most common subtype, tending to occur in the limbs, particularly in the thighs. Myxoid liposarcomas have an intermediate prognosis between well-differentiated and pleomorphic tumors. Spinal metastasis is usual but intradural involvement is extremely rare. We present an unusual case of a multicentric myxoid liposarcoma with intradural involvement. A 41-year-old woman complained of tingling sensation on her left arm. Radiological evaluation revealed multiple masses in her cervical spine, abdominal wall, liver, heart and right thigh, all of which were resected. She was histologically diagnosed with small round cell myxoid sarcoma and underwent adjuvant chemotherapy. However, magnetic resonance imaging analysis after 1 year revealed a large metastatic mass with bony invasion at the C6-T1 level. This mass consisted of extradural and intradural components causing severe compression of the spinal cord. She underwent resection via a posterior facetectomy of C6-7 and an anterior C7 corpectomy. However, the patient died of multiple metastases 18 months after the first diagnosis. KEY WORDS :Cervical spine˙ lntradural˙ Multicentric˙ Myxoid liposarcoma˙ Metastasis.

The clinicopathologic and immunohistochemical characteristics of nine cases of basaloid squamous carcinoma (BSC) of the upper aerodigestive tract are reported, along with the results of an in situ hybridization for human papilloma virus (HPV) DNA. The cases were selected through a review of 237 head and neck carcinomas, and were located in the supraglottic larynx (5), hypopharynx (2), and the base of tongue (2). The patients were 7 males and 2 females with the mean age of 62. BSCs were histologically characterized by lobules and nests of basaloid cells with scanty cytoplasm, comedonecrosis and adenoid features, and by concomitant presence of squamous cell carcinoma. Immunohistochemically, all BSCs showed positivity for high molecular weight cytokeratin (HMW CK) with heterogeneous or diffuse staining pattern, but lacked reactivity for neuroendocrine markers and bcl-2 oncoprotein. No HPV DNA was detected in BSCs. This study reaffirms that BSC is a rare carcinoma with a peculiar topographic distribution and distinct pathologic features.

There have been several reports that thymoma in human is a progressive disease, and that thymoma and thymic carcinoma form a continuum. We established a stable line of SV40T transgenic mice, which consistently produced thymic epithelial tumours progressing to thymic carcinoma within a predictable time span. Using this animal model and a morphological approach, thymic epithelial tumour progression was studied with reference to sequential changes at different time points in animals aged from 3 to 32 weeks. At all ages, SV40T was expressed in the nuclei of thymic epithelial cells; in these transgenic mice we observed the entire spectrum from cortical type thymoma to thymic carcinoma. Thymic size tended to increase with ageing in SV40T TG mice. While younger mice had predominantly cortical (organoid) or cortical thymoma, older mice had well-differentiated thymic carcinoma (WDTC) or poorly differentiated thymic carcinoma. When SV40T TG mice (248 line) reached a certain age, carcinoma of the thymus was present in all of them. Cortical-type thymoma became malignant within a predictable time span, suggesting a cortical thymoma-carcinoma sequence. When the mice were 9 weeks of age, the thymuses formed gross masses compatible with cortical thymoma. At 14 weeks of age, WDTC appeared against the background of cortical thymoma. Poorly differentiated thymic carcinoma was found after 15 weeks and affected all animals over 23 weeks of age. Most thymic carcinomas coexisted in varying proportions with cortical-type thymoma. Medullary thymomas did not develop in the mice, and no transition from medullary-type thymomas to thymic carcinomas was observed. In this SV40T transgenic mouse model, thymic carcinoma is clearly preceded by cortical-type thymoma. These transgenic mice may provide an interesting model for the progression from cortical thymoma to WDTC and/or high-grade carcinoma.