A 29-year-old woman, gravida 1, para 1, comes to the physician for the evaluation of a painful mass in her left breast for several days. She has no fevers or chills. She has not noticed any changes in the right breast. She has no history of serious illness. Her last menstrual period was 3 weeks ago. She appears anxious. Her temperature is 37°C (98.6°F), pulse is 80/min, respirations are 13/min, and blood pressure is 130/75 mm Hg. Examination shows a palpable, mobile, tender mass in the left upper quadrant of the breast. Ultrasound shows a 1.75-cm, well-circumscribed anechoic mass with posterior acoustic enhancement. The patient says that she is very concerned that she may have breast cancer and wishes further diagnostic testing. Which of the following is the most appropriate next step in the management of this patient?

Reassurance and clinical follow-up

A 59-year-old woman presents to her primary care provider with a 6-month history of progressive left-arm swelling. Two years ago she had a partial mastectomy and axillary lymph node dissection for left breast cancer. She was also treated with radiotherapy at the time. Upon further questioning, she denies fever, pain, or skin changes, but reports difficulty with daily tasks because her hand feels heavy and weak. She is bothered by the appearance of her enlarged extremity and has stopped playing tennis. On physical examination, nonpitting edema of the left arm is noted with hyperkeratosis, papillomatosis, and induration of the skin. Limb elevation, exercise, and static compression bandaging are started. If the patient has no improvement, which of the following will be the best next step?

Vascularized lymph node transfer

A 40-year-old man presents with a painless firm mass in the right breast. Examination shows retraction of the nipple and the skin is fixed to the underlying mass. The axillary nodes are palpable. Which of the following statements is FALSE regarding the above condition?

Lobular cancer is the most common breast cancer in males

BRCA2 mutations are associated with increased risk

These are positive for estrogen receptor

Endocrine therapy plays an important role in treatment

Gynecomastia may be caused by certain medications

A 61-year-old woman comes to the physician for a follow-up examination 1 week after undergoing right-sided radical mastectomy and axillary lymph node dissection for breast cancer. She says that she has been unable to comb her hair with her right hand since the surgery. Physical examination shows shoulder asymmetry. She is unable to abduct her right arm above 90 degrees. When she pushes against a wall, there is protrusion of the medial aspect of the right scapula. Injury to which of the following nerves is the most likely cause of this patient's condition?

Upper trunk of the brachial plexus

A 61-year-old woman presents to a surgical oncologist for consideration of surgical removal of biopsy-confirmed breast cancer. The mass is located in the tail of Spence along the superolateral aspect of the left breast extending into the axilla. The surgical oncologist determines that the optimal treatment for this patient involves radical mastectomy including removal of the axillary lymph nodes. The patient undergoes all appropriate preoperative tests and is cleared for surgery. During the operation, multiple enlarged axillary lymph nodes are present along the superolateral chest wall. While exposing the lymph nodes, the surgeon accidentally nicks a nerve. Which of the following physical examination findings will most likely be seen in this patient following the operation?

Scapular protrusion while pressing against a wall

Internal rotation, adduction, and extension of the arm

Weakness in arm flexion at the elbow and numbness over the lateral forearm

Weakness in shoulder abduction and numbness over the lateral shoulder

Weakness in wrist extension and numbness over the dorsal hand

An excisional biopsy is performed and the diagnosis of superficial spreading melanoma is confirmed. The lesion is 1.1 mm thick. Which of the following is the most appropriate next step in management?

Surgical excision with 1-2 cm safety margins and sentinel lymph node study

Surgical excision with 0.5-1 cm safety margins only

Surgical excision with 1 cm safety margins only

Surgical excision with 1-2 cm safety margins only

Surgical excision with 0.5-1 cm safety margins and sentinel lymph node study

A 63-year-old female with known breast cancer presents with progressive motor weakness in bilateral lower extremities and difficulty ambulating. Physical exam shows 4 of 5 motor strength in her legs and hyper-reflexia in her patellar tendons. Neurologic examination 2 weeks prior was normal. Imaging studies, including an MRI, show significant spinal cord compression by the metastatic lesion and complete erosion of the T12 vertebrae. She has no metastatic disease to the visceral organs and her oncologist reports her life expectancy to be greater than one year. What is the most appropriate treatment?

Surgical decompression and postoperative radiotherapy

Palliative pain management consultation

High-dose corticosteroids and clinical observation

Axillary lymph node dissection for USMLE Step 3: High-Yield Surgery Lessons

🗺️ Anatomy - Mapping the Axilla

Axillary Levels (Berg's Levels): Defined by their anatomical relationship to the Pectoralis Minor muscle, the key surgical landmark.
- Level I: Lymph nodes located lateral to the lateral border of the pectoralis minor.
- Level II: Nodes located posterior (deep) to the pectoralis minor muscle.
- Level III: Nodes located medial to the medial border of the pectoralis minor.

Axillary Anatomy: Nerves, Arteries, Veins, and Muscles

Key Nerves at Risk:
- Long Thoracic Nerve: Innervates serratus anterior. Injury → winged scapula.
- Thoracodorsal Nerve: Innervates latissimus dorsi. Travels with thoracodorsal artery/vein. Injury → weak arm adduction & internal rotation.
- Intercostobrachial Nerve: Sensory nerve often sacrificed. Injury → numbness/paresthesia of medial upper arm and axilla.

⭐ Lymphatic drainage typically flows sequentially: Level I → Level II → Level III. The long thoracic nerve is vulnerable as it runs along the chest wall on the surface of the serratus anterior.

🔪 Indications & Fallout

Indications for ALND:
- Clinically positive (palpable, biopsy-proven) axillary nodes.
- Positive sentinel lymph node biopsy (SLNB) in patients planned for mastectomy or with ≥3 positive nodes.
- Inflammatory breast cancer (after neoadjuvant chemotherapy).
- Failed SLNB procedure (non-visualization of sentinel node).

Fallout (Complications):
- Lymphedema: Most significant morbidity. Chronic arm swelling; risk ~20-30%.
- Nerve Injury:
  - Long Thoracic n. → Winged Scapula (Serratus Anterior).
  - Thoracodorsal n. → Weak arm adduction/extension (Latissimus Dorsi).
  - Intercostobrachial n. → Medial arm numbness (most common injury).
- Other: Seroma, infection, shoulder stiffness, chronic pain.

⭐ ACOSOG Z0011 Trial: For T1-T2 tumors with 1-2 positive sentinel nodes undergoing lumpectomy + whole-breast radiation, ALND offers no survival benefit over SLNB alone.

🔪 Management - The Surgical Blueprint

Indications for Axillary Lymph Node Dissection (ALND):
- Biopsy-proven nodal metastasis before surgery.
- Positive Sentinel Lymph Node Biopsy (SLNB), especially with ≥3 positive nodes.
- Clinically palpable, matted, or fixed axillary nodes.
- Inflammatory breast cancer.
- Failed SLNB mapping.
Surgical Boundaries (Levels I & II):
- Superior: Axillary vein (preserve).
- Lateral: Latissimus dorsi muscle.
- Medial: Pectoralis minor muscle.
- Anterior: Pectoralis major muscle.
⚠️ Nerves at Risk:
- Long Thoracic n.: Innervates serratus anterior. Injury → winged scapula.
- Thoracodorsal n.: Innervates latissimus dorsi. Injury → weak arm adduction/internal rotation.
- Intercostobrachial n.: Sensory. Injury → medial arm numbness.

⭐ Injury to the long thoracic nerve is a classic complication tested on exams, leading to a "winged scapula" due to paralysis of the serratus anterior muscle.

Major Complication: Chronic lymphedema.

🔬 Pathology - Grading the Haul

Adequacy of Dissection: A minimum of 10 lymph nodes is required for accurate staging from a Level I/II ALND. Fewer nodes may lead to understaging.
Pathologic Evaluation:
- Nodes are identified, counted, and sectioned for H&E staining.
- Immunohistochemistry (IHC) with cytokeratin antibodies can detect occult metastases.
Metastasis Classification (AJCC):
- Macrometastases: >2.0 mm
- Micrometastases: 0.2 mm to 2.0 mm
- Isolated Tumor Cells (ITCs): <0.2 mm or <200 cells
Extranodal Extension (ENE):
- Tumor invasion beyond the lymph node capsule.
- Associated with ↑ risk of recurrence and ↓ survival.

⭐ The number of positive axillary lymph nodes is the single most powerful prognostic factor for recurrence and survival in early-stage, non-metastatic breast cancer.

⚡ Biggest Takeaways

Indicated for biopsy-proven positive nodes or after a positive sentinel lymph node biopsy (SLNB).

Standard dissection removes Level I and II axillary nodes; Level III is spared unless involved.

Key nerve injuries: long thoracic (winged scapula), thoracodorsal (weak adduction), and intercostobrachial (medial arm numbness).

Lymphedema is the most significant long-term complication.

ACOSOG Z0011 trial supports omitting ALND in select patients with 1-2 positive SLNs undergoing breast-conserving therapy.

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