**Core Concept**
Splenectomy, or the removal of the spleen, is a surgical procedure that can be beneficial in certain clinical situations. The spleen plays a crucial role in filtering the blood, storing red blood cells, and housing the immune system's reticuloendothelial cells. In conditions where the spleen's function is compromised or it becomes a source of morbidity, splenectomy may be considered.

**Why the Correct Answer is Right**
The correct indication for splenectomy is hypersplenism, particularly in cases of thalassemia major, hereditary spherocytosis, or other conditions where the spleen is excessively sequestering or destroying red blood cells. This leads to pancytopenia, anemia, and other hematological abnormalities. Splenectomy helps alleviate these symptoms by removing the spleen's pathologic function. The procedure also reduces the risk of splenic rupture or infarction in these patients.

**Why Each Wrong Option is Incorrect**
**Option A:** Splenectomy is not typically performed for portal hypertension, as it may not address the underlying cause of variceal bleeding and can lead to increased risk of ascites and hepatic encephalopathy.
**Option B:** Splenectomy is not useful in the treatment of splenic abscess, as it may worsen the patient's condition by allowing bacteria to spread to other parts of the body.
**Option C:** Splenectomy is not indicated for splenic cysts, as they can often be managed conservatively or treated with percutaneous drainage.

**Clinical Pearl / High-Yield Fact**
In cases of splenic trauma, the decision to perform splenectomy should be individualized, considering factors such as the patient's age, overall health, and the extent of splenic injury. A non-operative approach may be preferred in stable patients with minor injuries.

**Correct Answer: C.** Splenic cysts.