S13C7aP5aTCellDysplasia

S13C7aP5a-1: The patterns have lichenoid qualities. In addition to band-like infiltrates which are confined to a widened papillary dermis, the epidermis shows hyperkeratosis, effacement of rete ridges, and spotty areas of liquefaction degeneration at the dermal-epidermal junction. Perivascular components are not a feature in the reticular dermis. This confinement of the infiltrate to the papillary dermis and the density of the infiltrate should provide a stimulus to examine the infiltrates for evidence of cytological atypia, with atypia as a marker identifying the infiltrates as those of a progressive T-cell dysplasia. There is little evidence of atypia at this magnification. The patterns are compatible with a mild T-cell dysplasia as seen in the setting of “parapsoriasis” (clinically, the lesion was thought to be compatible with keratosis lichenoides chronica).

S13C7aP5a-2: The area outlined in green arrows in S13C5P2-1 is seen at a higher magnification. The mild atypia in the lymphoid component in this field would not qualify the lesion as a convincing marker for a progressive T-cell dysplasia; the lesion would qualify at most as a mild T-cell dysplasia of indeterminate type. In this field, there is a high component of histiocytes; the patterns are somewhat granulomatous. Focal granulomatous components are occasionally a feature of lesions in the category of progressive T-cell dysplasias. The presence of granulomas in such lesions merely adds to the difficulties in the interpretation of the mild T-cell dysplasias.

S13C7aP5a-3: This is another example of a psoriasiform T-cell dysplasia with a high component of histiocytes. The lymphoid cells are mostly small. It is difficult to assign the lesion to a category of progressive dysplasia simply on the basis of degree of cytological atypia; the lesion qualifies as a mild T-cell dysplasia of indeterminate type.

S13C7aP5a-4: In this field from the same lesion as S13C5P3-3, green arrows outline a small granuloma at the tip of a rete ridge. The granulomatous components add to the difficulty in assigning the lesion to either a reactive, or neoplastic, category. The lymphoid component of the dermis does not show significant cytologic atypia.


	S13C7aP5a-5: At higher magnification, there is variability in both nuclear size and outline. The lymphoid cells are loosely spaced; occasional lymphoid cells have enlarged nuclei with convoluted outlines (transformed T lymphocytes).

S13C7aP5a-6: A biopsy specimen from a lesion later in the clinical course of this progressive T-cell neoplasm shows a high component of transformed T-cells (i.e., cells with large nuclei, signifying a high grade dysplasia); nuclei are enlarged, convoluted, and closely spaced. Nuclear chromatin is dense and uniformly distributed; nuclear membranes are “heavy.” High grade patterns of this type herald the emergence of tumors and disseminated disease.

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