Okay, let's tackle this question. The patient is a 65-year-old man with multiple lesions on his penis that he's had for two months. The physical exam shows shiny, soft, erythematous plaques on the glans and foreskin. The biopsy shows neoplastic epithelial cells with intercellular bridges and invasion into the dermis.

First, I need to recall the different types of penile neoplasms. The key here is the histological features mentioned: neoplastic epithelial cells connected by intercellular bridges. Intercellular bridges are a hallmark of squamous cell differentiation. Carcinoma in situ (CIS) of the penis, also known as Bowen's disease, typically presents as erythematous, scaly plaques and shows full-thickness dysplasia without invasion. But the question mentions invasion into the dermis, which suggests a more advanced stage.

If the cells have intercellular bridges and are invading, that sounds like squamous cell carcinoma (SCC) of the penis. SCC is the most common type of penile cancer and presents as nodules or plaques. The presence of invasion into the dermis would classify it as invasive SCC.

The other options might include other types like melanoma, which would have different histological features (atypical melanocytes, not intercellular bridges), or basal cell carcinoma, which usually has palisading basaloid cells and a peripheral palisade, not intercellular bridges. Metastatic carcinoma is less likely here given the primary site.

So the correct diagnosis here is invasive squamous cell carcinoma. The key points are the histological features of intercellular bridges (squamous differentiation) and invasion into the dermis.

**Core Concept**
This question tests the histological distinction between penile intraepithelial neoplasia (Carcinoma in Situ) and invasive squamous cell carcinoma (SCC). Intercellular bridges are a hallmark of squamous differentiation, while invasion into the dermis defines invasive SCC.

**Why the Correct Answer is Right**
The biopsy shows neoplastic epithelial cells with intercellular bridges (squamous cell features) and stromal invasion. Invasive SCC of the penis is characterized by these histological findings. Clinically, it presents as erythematous plaques or nodules on the glans or foreskin, aligning with this patient’s presentation. In contrast, Carcinoma in Situ (Bowen’s disease) remains confined to the epidermis without invasion.

**Why Each Wrong Option is Incorrect**
**Option A:** *Basal cell carcinoma* lacks intercellular bridges and shows palisading basaloid cells, not dermal invasion in this context.
**Option B:** *Penile melanoma* arises from melanocytes, exhibits atypical melanocytes, and lacks intercellular bridges.
**Option C:** *Metastatic carcinoma* is unlikely here; primary penile SCC is far more common and has distinct squamous features.

**Clinical Pearl / High-Yield Fact**
Invasive penile SCC is staged using the TNM system. Early diagnosis (e.g., Carcinoma in Situ) allows for less aggressive therapy, but invasion into the dermis necessitates wide local excision or circumcision. Remember: intercellular bridges + dermal invasion

✓ Correct Answer: D. Squamous cell carcinoma