ABSTRACT
Tetragametic chimeras are due to the fusion of 2 different zygotes after fertilization. When occurring between embryos of different chromosomal sex, the phenotype ranges from fertile individuals to infertile patients and even to patients with variations in sex development. Here, we report 3 new cases of XX/XY chimeras, one in a young boy carrying an abnormal gonad which turned out to be an ovary and 2 in phenotypically normal infertile men, one of whom had been diagnosed previously as a XX-SRY negative male. These cases highlight the importance of combining several cytogenetic and molecular techniques on different tissues for a proper diagnosis and an appropriate prognosis.
ABSTRACT
Nora's lesion, also known as bizarre parosteal osteochondromatous proliferation (B.P.O.P.), involves mostly the small tubular bones of the hands and feet. Histologically, it is characterized by a proliferation of chondroid, bony and fibrous tissues, sometimes with high cellular density, bizarre chondrocytes but is devoid of cellular atypia and necrosis. Distinct blue color is noted at the interface of bone and cartilage. The most important lesions that present differential diagnostic problems are chondrosarcoma, parosteal osteosarcoma and florid reactive periostitis. The lesion is benign but may recur locally in as many as 55%. The clinical and pathological findings of four cases of Nora's lesion are presented.
