is a distinctive pattern of passive migration into epithelial structures that is not otherwise attributable to the normal function of innate and adaptive immunity," the researchers explained.
Each case exhibited a well-defined grenz zone without epidermotropism
The skin biopsy showed a predominance of folliculotropism (Figure 2c), compared to a less-remarkable epidermotropism
, with intraepidermal clusters of atypical lymphocytes larger than benign recruited dermal lymphocytes, as well as perinuclear vacuolization seen in the patch- and plaque-stage of MF (H&E stain, 2a, b.
Skin biopsies of T-PLL cutaneous involvement classically show infiltrate of variable density of atypical lymphocytes in the superficial dermis, with a perivascular and periadnexal distribution with no epidermotropism
One observes an interface infiltrate, and in the more advanced lesions, definite epidermotropism
Histopathology of poikilodermatous lesions discloses an atypical T-cell infiltrate in the papillary dermis, often with evident epidermotropism
Histopathologically, BPDCN in the skin is characterized by a diffuse infiltrate of medium-sized blasts with high N:C ratio, scant cytoplasm, finely dispersed chromatin, and prominent nucleoli in the dermis underlying a Grenz zone without epidermotropism
The pathologist noted epidermotropism
, exocytosis with atypical lymphoid cells, and a "predominance of T cells," leading to a diagnosis of "probable mycosis fungoides.
Additionally, there were scattered immature myeloid and erythroid precursors and areas of focal epidermotropism
Although abnormal T cells can be detected in skin biopsies of patients with L-HES, they usually show a perivascular and dermal pattern of infiltration and do not show significant epidermotropism
or other features of mycosis fungoides, such as Pautrier microabscesses or formation of patches, plaques, and tumors.
Epidermis showed ulceration with absence of epidermotropism
MF is characterized by small to medium-sized lymphocyte infiltrate in the dermis with epidermotropism