**Core Concept**
Pentamidine is an antiprotozoal medication used primarily to treat Pneumocystis jirovecii pneumonia (PCP) in immunocompromised patients. It can cause various pulmonary and extrapulmonary side effects due to its mechanism of action and toxicity profile.

**Why the Correct Answer is Right**
Pentamidine can indeed cause upper lobe infiltrates, cavitation, and extrathoracic manifestations, such as hyperglycemia, hypocalcemia, and adrenal insufficiency, as a result of its effects on pancreatic beta cells, calcium homeostasis, and adrenal function. The medication's toxicity profile is closely related to its ability to interfere with cellular processes, leading to these adverse effects.

**Why Each Wrong Option is Incorrect**
**Option A:** Upper lobe infiltrates are a known side effect of pentamidine therapy, which can be a result of its direct toxic effects on lung tissue or as a manifestation of PCP treatment failure.
**Option B:** Cavitation is also a recognized complication of pentamidine therapy, particularly in patients with pre-existing lung disease or those who are malnourished.
**Option C:** Extrathoracic manifestations, such as endocrine dysfunction, are a well-documented consequence of prolonged pentamidine use.
**Option D:** This option is correct because the question asks for an exception, and the correct answer is "None," implying that all the listed options (A, B, and C) are potential side effects of pentamidine therapy.

**Clinical Pearl / High-Yield Fact**
Pentamidine can cause a dose-dependent increase in insulin resistance, which may lead to hyperglycemia and diabetes mellitus in some patients. This side effect is particularly relevant in patients with pre-existing glucose intolerance or those who are at risk of developing type 2 diabetes.

✓ Correct Answer: D. None