Furthermore, papillary tumors may metastasize to the lungs and produce a few nodules or the lung fields may exhibit a snowflake appearance throughout. Other characteristics of the papillary carcinoma is that E.M. shows increased mitochondria, increased RER, as well as increased apical microvilli. Moreover, papillary carcinomas have an indolent growth, and 40 percent of cases spread out of the capsule. Associated mutations
Mutations associated with papillary thyroid cancer are mainly two forms of chromosomal translocation and one form of point mutation. These alterations lead to activation of a common carcinogenic pathway—the MAPK/ERK pathway. Chromosomal translocations involving the RET proto-oncogene (encoding a tyrosine kinase receptor that plays essential roles in the development of neuroendocrine cells) located on chromosome 10q11 occur in approximately a fifth of papillary thyroid cancers. The fusion oncoproteins generated are termed RET/PTC proteins (ret/papillary thyroid carcinoma), and constitutively activate RET and the downstream MAPK/ERK pathway. The frequency of ret/PTC translocations is significantly higher in papillary cancers arising in children and after radiation exposure. The gene NTRK1 (encoding the TrkA receptor), located on chromosome 1q, is similarly translocated in approximately 5 percent to 10 percent of papillary thyroid cancers.Approximately a third to a half of papillary thyroid carcinomas harbor point mutations in the BRAF oncogene, also activating the MAPK/ERK pathway. In those cases the BRAF mutations found were V600E mutation. After performing a multivariate analysis, it was found that the absence of tumor capsule was the only parameter associated (P=0.0005) with BRAF V600E mutation.
Perforating granuloma annulare is a skin condition of unknown cause, usually appearing on the dorsal hands, presenting as papules with a central keratotic core. : 704 These lesions are often seen on the hands, arms, and ankles. Granuloma Annulare is characterized by rings of closely set, small, smooth, firm papules, usually skin colored, but they also may be slightly erythematous or have a purplish hue. Lesions vary in size from 1cm to 5cm. They are generally asymptomatic and nonpruritic (Fairlie, 2004). Reports of associations between Granuloma Annulare and diabetes mellitus, thyroid disease, malignancies, drug allergies, hypertension, arthritis, AIDS, and other conditions are being evaluated, but to date, no consistent association has been found (Rigopoulos et al., 2005). See also
Granuloma annulare
Skin lesion

References


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