Nipple Discharge - Causes, Classification, and Diagnosis

1. Classification: Physiologic vs. Pathologic

Physiologic Discharge

Pathologic Discharge

"Any nipple discharge that is spontaneous is considered pathologic."

• Mulholland and Greenfield's Surgery, 7e

2. Causes of Nipple Discharge

Physiologic / Hormonal

• Galactorrhea (bilateral milky): elevated prolactin from pituitary adenoma, hypothyroidism, chest wall trauma, medications
• Drug-induced: oral contraceptives, metoclopramide, phenothiazines, SSRIs, antipsychotics

Non-neoplastic (Benign Pathologic)

• Intraductal papilloma - the most common cause of pathologic nipple discharge; benign epithelial lesion with stroma growing within a duct
• Duct ectasia - ductal dilatation with loss of elastin, chronic inflammation; typically in older/perimenopausal women; discharge is often green/brown
• Fibrocystic change - often premenopausal, multiduct, bilateral, greenish/brownish, cyclic with menses
• Periductal mastitis / subareolar abscess
• Papillomatosis

Neoplastic

• Ductal carcinoma in situ (DCIS) - most common malignant cause (5-15% of pathologic nipple discharge)
• Invasive carcinoma
• In males: isolated nipple discharge is very abnormal - up to 9% of male breast malignancy presents this way

3. Diagnostic Workup

History (Key Questions)

1. Is the discharge spontaneous or expressed?
2. Unilateral or bilateral?
3. Single duct or multiple ducts?
4. Color and nature (bloody, serous, milky)?
5. Associated breast mass?
6. Relation to menstrual cycle?
7. Pre- or postmenopausal?
8. Medications (OCP, antipsychotics, SSRIs, metoclopramide)?
9. History of trauma, thoracotomy, or endocrine disorders?

Physical Examination

• Inspect nipple and areola for Paget disease, eczema, retraction
• Palpate each quadrant from periphery to nipple-areolar complex to identify the "trigger point" (the quadrant that, when compressed, produces discharge)
• Identify whether single or multiple ducts involved
• Perform occult blood test on the discharge
• Visual field testing if pituitary/chiasmal syndrome suspected

Laboratory Tests

• Serum prolactin (elevated in pituitary adenoma, hypothyroidism, medications)
• Thyroid function tests (TSH, free T4)
• Quantitative beta-hCG (rule out pregnancy)
• For pituitary adenoma: thin-section CT or MRI sella turcica; visual field testing

4. Imaging Investigation

For Physiologic Discharge

• No further imaging required if truly physiologic (nonprovoked, bilateral, multiductal)

For Pathologic Discharge

• Mammogram (age-appropriate; recommended for all >30 years)
• Directed subareolar ultrasonography
• These are the first-line investigations for all pathologic discharge

• A thin cannula is placed into the discharging duct and a small amount of water-soluble contrast is instilled
• Abnormal findings: intraductal filling defect, ductal wall irregularity, or abrupt duct truncation/obstruction
• The image below shows an intraductal papilloma on ductogram:

Note: A normal ductogram does not exclude cancer. The procedure is also painful and not commonly performed at many centers.

• Has rapidly replaced ductography as the preferred tool for persistent/pathologic discharge when mammogram and ultrasound are negative
• Identifies underlying pathology in 19-96% of cases where other imaging is negative
• Also useful when clinical suspicion remains high despite negative conventional imaging

• Fiberoptic ductoscope placed directly into the involved duct (usually in the operating room)
• Allows direct visualization of intraductal lesions
• Enables more precise surgical excision by guiding the outer sheath as a surgical guide

5. Biopsy and Surgical Management

Surgical Technique - Terminal Duct Excision

• Periareolar incision
• Intraoperative duct identification: lacrimal duct probe or methylene blue dye injection
• Excise duct from proximal to distal extent (~2-3 cm)
• If multiple ducts involved: central or total terminal duct excision
• Risks: inability to breastfeed, nipple hypersensitivity or hyposensitivity

6. Summary Algorithm

Nipple Discharge
       |
 ┌─────┴──────┐
Physiologic  Pathologic
(bilateral,  (spontaneous,
multiductal, unilateral,
non-spont.)  single duct)
       |           |
  Reassure,   Mammogram + USS
  stop         (age-appropriate)
  manipulation      |
              ┌─────┴──────┐
          Normal       Abnormality
              |             |
          MRI breast    Core needle
          or Ductogram    biopsy
              |
      ┌───────┴────────┐
  Normal/         Focal lesion
  persistent         |
  symptoms      Core biopsy ± excision
      |
  Terminal duct
  excision

Key Points to Remember

• Most nipple discharge is benign - <10% of spontaneous nipple discharge is malignant
• Intraductal papilloma is the #1 cause of pathologic nipple discharge
• Bloody + unilateral + spontaneous + single duct = high suspicion, always investigate
• Galactorrhea in a non-lactating woman requires serum prolactin, TSH, and hCG before breast-focused workup
• Breast MRI has largely replaced ductography in current practice for negative conventional imaging
• Postmenopausal nipple discharge - all cases are significant and warrant specialist referral
• Male nipple discharge - always abnormal; investigate aggressively for malignancy

Osteoarthritis (OA) - Brief Overview

Definition

Types

• Prevalence increases exponentially after age 50 - about 40% of people >70 are affected
• Women are disproportionately affected

Pathogenesis

Morphological Changes (Pathology)

Joints Commonly Affected

• Knees and hips (weight-bearing)
• Lower lumbar and cervical vertebrae
• Proximal (PIP) and distal (DIP) interphalangeal joints of fingers
• First carpometacarpal joint (base of thumb)
• First metatarsophalangeal joint (big toe)

Clinical Features

• Joint pain that worsens with use and improves with rest (early); later becomes constant
• Morning stiffness (<30 minutes - distinguishes from RA which is >1 hour)
• Crepitus on movement
• Limitation of range of movement
• Joint deformity (no joint fusion - unlike RA)
• Spinal osteophytes → nerve root compression → radicular pain, muscle spasm, neurological deficits

"The level of disease severity detected radiographically does not correlate well with pain and disability."

• Robbins & Kumar Basic Pathology

OA vs Rheumatoid Arthritis (Quick Comparison)

Diagnosis

• Clinical: history + examination (pain pattern, stiffness, crepitus)
• X-ray (gold standard): joint space narrowing, subchondral sclerosis, osteophytes, subchondral cysts
• Labs: no specific markers; used to exclude other arthritis (normal ESR, CRP, RF)
• MRI: detects early cartilage loss and soft tissue changes before X-ray changes appear

Management (Brief)

• Non-pharmacological: exercise, weight loss, physiotherapy, activity modification, assistive devices
• Pharmacological: paracetamol, NSAIDs (oral/topical), intra-articular corticosteroids, duloxetine (for refractory pain)
• Surgical: joint replacement (arthroplasty) for severe, refractory cases

"There are no treatments to prevent or halt the progression of OA."

• Robbins & Kumar Basic Pathology