**Question:** Which of the following is epitheloid type of nevus cell?

A. Spitz nevus
B. Blue nevus
C. Dysplastic nevus
D. Melanoma

**Core Concept:** Epitheloid cells are a characteristic feature of certain benign melanocytic lesions. These cells have an epithelioid (spindle-shaped) appearance due to their elongated nuclei and eosinophilic cytoplasm. The epitheloid type of nevus cell is observed in some melanocytic lesions, which can help differentiate them from malignant melanoma.

**Why the Correct Answer is Right:** The correct answer is the epitheloid variant of the Spitz nevus (Option A) and Blue nevus (Option B). These lesions are characterized by the presence of epitheloid melanocytes, which have an epithelioid morphology. In Spitz nevus, the epitheloid cells form a "keyhole" pattern. In blue nevus, the epitheloid cells are arranged in a "salt and pepper" pattern, giving the lesion its characteristic blue appearance.

**Why Each Wrong Option is Incorrect:**

**Option C - Dysplastic nevus:** Dysplastic nevi are characterized by the presence of atypical melanocytes, but they do not typically exhibit epitheloid morphology. Atypical melanocytes in dysplastic nevi have larger, irregular, and hyperchromatic nuclei, and do not form the keyhole or salt and pepper patterns seen in Spitz nevus and blue nevus.

**Option D - Melanoma:** In melanoma, the epitheloid cells are not present. Instead, melanoma is characterized by the presence of invasive, irregular, and pleomorphic melanocytes with prominent nucleoli. Additionally, melanoma cells exhibit mitotic activity and infiltration into surrounding tissues, which is not seen in the epitheloid variants of Spitz nevus and blue nevus.

**Clinical Pearl:** The epitheloid variant of Spitz nevus and blue nevus are benign lesions, while melanoma is an aggressive malignant tumor with distinct differences in cell morphology and behavior. A thorough examination of the lesion's morphology, pattern, and associated clinical features can help differentiate these entities and guide appropriate management and surveillance.

In summary, the epitheloid variant of Spitz nevus and blue nevus are benign melanocytic lesions characterized by the presence of epitheloid melanocytes, whereas melanoma exhibits distinct differences in cell morphology and behavior. A comprehensive assessment of the lesion's appearance, pattern, and clinical features is essential in making an accurate diagnosis and determining appropriate management and follow-up strategies for patients.