**Core Concept**
The patient's presentation suggests a locally invasive neoplasm of the nose, likely originating from the epithelial lining of the nasal vestibule.

**Why the Correct Answer is Right**
The broadening of the nasal dorsum and infiltrating lesion involving the nasal vestibule and upper lip are characteristic features of a rare but aggressive tumor called Rhinopharyngeal Cancer or more specifically, Nasopharyngeal Carcinoma (NPC) can be ruled out due to its typical presentation and involvement of the nasopharyngeal region. However, given the location of the lesion, the most likely diagnosis is a type of cancer that originates from the epithelial lining of the nose. The correct answer, Squamous Cell Carcinoma (SCC), is the most common type of cancer affecting the nasal cavity and paranasal sinuses, often presenting with nasal obstruction, crusting, and infiltrating lesions.

**Why Each Wrong Option is Incorrect**
* **Option B:** Basal Cell Carcinoma (BCC) is a type of skin cancer that primarily affects sun-exposed areas, but it is less common in the nasal vestibule and typically presents with a more superficial, well-defined lesion.
* **Option C:** Melanoma is a type of skin cancer that originates from melanocytes, but it is rare in the nasal vestibule and typically presents with a pigmented lesion.
* **Option D:** Adenocarcinoma is a type of cancer that originates from glandular tissue, but it is less common in the nasal vestibule and typically presents with a more subtle, non-infiltrating lesion.

**Clinical Pearl / High-Yield Fact**
The nasal vestibule is a common site for squamous cell carcinoma, especially in individuals with a history of smoking and prolonged exposure to carcinogens.

**Correct Answer:** C. Squamous Cell Carcinoma.