**Core Concept:** Breast lumps are a common clinical finding in women and are typically evaluated to rule out breast cancer or other pathologies. The correct sequence of investigations depends on the clinical presentation and history.

**Why the Correct Answer is Right:**

Correct Answer: C. Mammography

In this scenario, mammography is the recommended initial investigation. A mammogram is a type of X-ray that provides detailed images of the breast tissue, allowing for the detection of small, subtle changes that may indicate breast cancer or other breast pathologies.

**Why Each Wrong Option is Incorrect:**

A. Fine-needle aspiration cytology (FNAC) - FNAC is a diagnostic procedure that involves obtaining a sample of tissue or fluid from a body part for microscopic examination. While it can be helpful in further evaluation, it is not the first-line investigation for a suspicious breast lump.

B. Ultrasound - Ultrasound is a useful tool for assessing breast lesions, but it may not detect calcifications or microcalcifications, which are common in breast cancer. Mammography is more effective in detecting these subtle changes.

D. Clinical examination - Clinical examination alone may not provide sufficient information about the nature and extent of the lump, making mammography a more appropriate initial investigation.

**Why Clinical Pearl:**

Mammography is crucial for ruling out breast cancer at an early stage, which increases the chances of successful treatment outcomes. It is essential for women over 40 years of age to have regular mammographic screening to detect breast cancer at an early stage, which improves prognosis and outcomes.

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**Question:** A 45-year-old woman presents with a hard and mobile lump in the breast. Which of the following is the correct initial investigation?

A. Fine-needle aspiration cytology
B. Ultrasound
C. Mammography
D. Clinical examination

**Correct Answer:** C. Mammography

The correct initial investigation for a suspicious breast lump in a 45-year-old woman is mammography. Mammography is a non-invasive test that uses X-rays to create detailed images of the breast tissue, allowing for the detection of subtle changes that may indicate breast cancer or other breast pathologies. Mammography is particularly effective in detecting microcalcifications and calcifications, which are common in breast cancer but may be missed by ultrasound or clinical examination alone.

While ultrasound can provide valuable information about the nature and extent of the lump, mammography is more appropriate for ruling out breast cancer, which has better sensitivity and specificity than ultrasound or clinical examination. Clinical examination is crucial for assessing the size, shape, and mobility of the lump but may not be sufficient for detecting microcalcifications or calcifications, which are early indicators of breast cancer. Fine-needle aspiration cytology (FNAC) is a diagnostic procedure that involves obtaining a sample of tissue for microscopic examination but is not the first-line investigation for a breast lump.

In conclusion, mammography is the most appropriate initial investigation for a suspicious breast lump in a 45-year-old woman to rule out breast cancer and other breast