Mycosis Fungoides : Tumor Stage

Comments:
Mycosis fungoides (MF) - Tumor Stage: The tumor stage shows mushroom-like, bulging nodular lesions that are often ulcerated. Microscopically, there are dense collections of atypical lymphoid cells diffusely infiltrating the reticular dermis, sometimes involving the subcutaneous fat. The infiltrates are ill-defined or have vaguely nodular configuration.

In addition to the atypical lymphoid cells with convoluted, cerebriform nuclei, the infiltrate frequently shows a few highly pleomorphic cells with large vesicular nuclei and prominent nucleoli. When >25% of the infiltrate consists of large cells, it is referred to as large cell transformation (discussed later). Mitotic activity is brisk. Abnormal mitoses may be seen.

Epidermotropism is minimal or entirely absent in the tumor stage in some cases of MF. This loss of skin-homing ability of the tumor cells coincides with their capacity to invade internal organs.