Lambda sign or twin peak sign is seen in
**Core Concept**
The lambda sign or twin peak sign refers to a radiological finding observed on ultrasound imaging, particularly in the context of abdominal or pelvic pathology. This sign is characterized by a specific appearance of the bowel or other structures, which resembles the Greek letter lambda (λ) or two peaks.
**Why the Correct Answer is Right**
The lambda sign is typically seen in cases of ovarian torsion, where the twisted ovary and its associated mesosalpinx (fallopian tube) take on a characteristic lambda or twin peak shape. This occurs due to the twisting of the ovarian pedicle, which leads to a constricted and kinked appearance of the affected ovary and its surrounding structures. The ultrasound findings in ovarian torsion may also include a "whirlpool" or "twisted" appearance of the ovarian vessels and a reduction or absence of blood flow to the affected ovary.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the lambda sign is not typically associated with other abdominal or pelvic pathologies such as appendicitis or diverticulitis.
**Option B:** Option B is incorrect because the lambda sign is not a characteristic finding in cases of ectopic pregnancy.
**Option C:** Option C is incorrect because the lambda sign is not typically seen in cases of ovarian cysts or other benign ovarian masses.
**Clinical Pearl / High-Yield Fact**
The lambda sign is a valuable ultrasound finding that can help diagnose ovarian torsion, a potentially life-threatening condition that requires prompt surgical intervention. In addition to the lambda sign, other ultrasound findings that may support the diagnosis of ovarian torsion include a twisted or kinked appearance of the ovarian pedicle and a reduction or absence of blood flow to the affected ovary.
**Correct Answer: D. Ovarian torsion**