Which form of canine cutaneous lymphoma is characterized by CD8+ T cell infiltration of the dermis and superficial panniculus?

The form of canine cutaneous lymphoma characterized by CD8+ T cell infiltration of the dermis and superficial panniculus is indeed mycosis fungoides. This type of lymphoma is a variant of cutaneous T-cell lymphoma, and it is often associated with a specific immunophenotype that includes the presence of CD8+ T cells in the affected skin.

Mycosis fungoides manifests with various skin lesions, which can include plaques, nodules, and potentially more extensive skin involvement. The pathology typically shows an infiltrate of atypical lymphocytes in the dermis, and the CD8+ T cell profile is significant in distinguishing these lesions from other skin tumors. This characteristic helps pathologists accurately diagnose and differentiate mycosis fungoides from other forms of cutaneous neoplasms, which may not exhibit the same immunophenotypic profile or histological features.

In contrast to the other options, sarcoid (also known as equine sarcoid) and fibrosarcoma have distinct cellular profiles and do not typically present with a CD8+ T cell infiltration pattern that is seen in mycosis fungoides. Sarcoid, for example, is associated with fibroblastic proliferation and is not classified