**Core Concept**
Pautrier's micro-abscess is a characteristic histological feature of a specific autoimmune skin condition. It is characterized by a cluster of lymphocytes that invade and destroy the epidermis, leading to a distinctive histological appearance.

**Why the Correct Answer is Right**
Pautrier's micro-abscess is a hallmark feature of mycosis fungoides, a type of cutaneous T-cell lymphoma. The lymphocytes involved in Pautrier's micro-abscess are typically CD4+ T cells that infiltrate the epidermis, leading to the formation of aggregates of lymphocytes within the epidermal layer. This process is thought to be mediated by the interaction of CD4+ T cells with other immune cells and the epidermal cells, leading to the destruction of the epidermis.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Pautrier's micro-abscess is not a feature of psoriasis, which is characterized by thickening of the epidermis and the presence of Munro's micro-abscesses, which are collections of neutrophils within the epidermis.

**Option B:** This option is incorrect because Pautrier's micro-abscess is not a feature of dermatitis herpetiformis, which is characterized by the presence of IgA deposits in the dermal papillae and a granular or vesicular appearance on histology.

**Option C:** This option is incorrect because Pautrier's micro-abscess is not a feature of lupus erythematosus, which is characterized by a lymphocytic infiltrate in the dermis and the presence of antinuclear antibodies.

**Clinical Pearl / High-Yield Fact**
Pautrier's micro-abscess is a critical histological feature that distinguishes mycosis fungoides from other types of cutaneous lymphomas and autoimmune skin conditions. It is essential to recognize this feature to make an accurate diagnosis and initiate appropriate treatment.

**Correct Answer: D. Mycosis fungoides.**