Objective To investigate clinicopathological characteristics and differential diagnosis of malignant melanoma of the skin.Method The histopathological characteristics and clinical date of 29 cases were analyzed retrospectively.Results By microscopy,the cells type were composed of epithelioid,spindle,nevus-like,hylocyte and tumour giant.The tumour cells were arranged in nest-like,beam-like,adeniform fascicle-like,laciform,whirlpool and diffusion pattern.The immunohistochemically,the positive rates of S-100 protein,HMB45,Vimentin in 29 cases were 100%,93%,93%.Conclusion The histopathological structures and morphological characters of malignant melanoma are complex.The diagnosis relies mainly on histopathological and immunohistochemically findings.

Objective To investigate clinicopathological characteristics and differential diagnosis of primary thyroid lymphoma(PTL).Methods Two cases of PTL were studied and confirmed by histologic and immunohistochemical staining,and 199 cases with valid clinical information of PTL reported in literature by other authors in recent 10 years were reviewed.Results PTL occurred more often in old female,presenting as tumour in unilateral or bilateral thyroid,B-cell type were accounted for 94.5%(190/201) and of T-cell type,5.5% only(11/201).Conclusion PTL is a rare neoplasm.The diagnosis relies mainly on histopathological and immunohistochemical findings.