Appendicitis: Although appendicitis is more common in younger populations, it can occur at any age. The presentation of right lower quadrant (RLQ) abdominal pain is classic for appendicitis, making it a leading consideration in this case.

Diverticulitis: This condition is more common in older adults and can present with RLQ pain if the diverticula are located in the sigmoid colon, which can sometimes refer pain to the right side.
Cholecystitis: Inflammation of the gallbladder can cause right upper quadrant pain but can sometimes radiate or be perceived in the RLQ, especially if the gallbladder is distended or if there is associated peritonitis.
Intestinal Obstruction: This can cause abdominal pain that may be localized to the RLQ, depending on the site of obstruction. Older adults are at higher risk due to increased incidence of adhesions from previous surgeries.
Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease can present at any age and may cause chronic or acute RLQ pain due to inflammation of the bowel.

Ectopic Testis or Torsion: Although rare in this age group, testicular torsion can cause severe pain that may be referred to the abdomen, including the RLQ.
Ovarian Torsion: Similarly, in females, ovarian torsion is a surgical emergency, but given the patient is male, this is less relevant. However, it's a reminder to consider atypical presentations of abdominal pain.
Ruptured Abdominal Aortic Aneurysm (AAA): This is a life-threatening condition that can present with abdominal pain, which may be perceived in the RLQ, especially if the rupture involves the right iliac artery.
Mesenteric Ischemia: This condition can cause severe abdominal pain out of proportion to the physical examination findings and is more common in older adults with vascular disease.

Carcinoid Tumor: These tumors can cause abdominal pain due to bowel obstruction, intussusception, or mesenteric fibrosis, but they are less common.
Meckel's Diverticulum: A congenital anomaly of the small intestine that can cause pain, obstruction, or bleeding, but it's rare to present for the first time in older adults.
Right Lower Lobe Pneumonia: Referred pain from a lower lobe pneumonia can sometimes be perceived in the abdomen, including the RLQ, especially if there is associated pleurisy.