**Question:** In tissue, Coccidioides immitis produces ?

A. Arcoidea
B. Arcoides
C. Arcoid spherules
D. Arcoid cysts

**Core Concept:**
Coccidioides immitis is a fungal pathogen responsible for causing coccidioidomycosis, also known as Valley Fever. This infection primarily affects the lungs, although it can also involve other organs. Coccidioides immitis produces spherules and cysts as part of its life cycle.

**Correct Answer: C. Arcoid spherules**

**Why the Correct Answer is Right:**
Coccidioides immitis is an etiological agent of coccidioidomycosis, a fungal infection caused by dimorphic fungi. In tissue, Coccidioides immitis primarily produces arcoid spherules when infecting the host. These spherules are the transition form between yeast cells (macroconidia) and arthroconidia. Arcoid spherules are spherical, capsulated structures that contain a central fungal mass and surround it with a hyphal wall.

**Why Each Wrong Option is Incorrect:**

A. **Arcoidea** is incorrect because it refers to a group of fungi, not a specific production by Coccidioides immitis.
B. **Arcoides** is also incorrect, as it is a misspelling of Arcoidea and does not represent a correct description of the fungal production.
D. **Arcoid cysts** are not produced by Coccidioides immitis. Arcoid cysts are a term describing the cyst stage of some parasites, not fungi.

**Clinical Pearl:**
In the context of coccidioidomycosis, understanding the correct term for the tissue response to Coccidioides immitis infection is essential. Arcoid spherules are crucial for diagnosing the disease, as they are unique to Coccidioides immitis and can aid in distinguishing it from other fungal infections.