What is the management of pseudoangiomatous stromal hyperplasia (PASH)?

Management of Pseudoangiomatous Stromal Hyperplasia (PASH)

Core needle biopsy (CNB) is sufficient to confirm PASH when an abnormal imaging finding or suspicious physical examination is present, and surgical excision is not routinely necessary after diagnosis unless there are concerning features. 1

Clinical Presentation and Diagnosis

• PASH is a benign mesenchymal proliferative lesion of the breast that typically presents as:

  • A palpable mass (in 56-96% of cases) 2, 3
  • An incidental finding on imaging (in remaining cases) 2
  • Most common in premenopausal and perimenopausal women (median age 41-45 years) 1, 2, 3

• Diagnostic approach:

  1. Imaging (mammogram, ultrasound) - findings are nonspecific 1, 4
  2. Core needle biopsy - confirms diagnosis in approximately 64-65% of cases 1, 2
  3. Histopathological confirmation - shows characteristic stromal proliferation with slit-like spaces

Management Algorithm

For PASH diagnosed on CNB:

1. If PASH is diagnosed on CNB with no suspicious clinical or radiological features:

   • Close monitoring with follow-up imaging at 6-month intervals is appropriate 2
   • No immediate surgical excision is required 1, 5

2. Surgical excision is indicated if any of the following are present:

   • Large lesion size (>3 cm) 1
   • Progressive growth of the lesion 1
   • Suspicious radiological findings 2
   • Inconclusive biopsy results 2
   • Discordance between imaging and pathology findings 5
   • Symptomatic mass causing discomfort 3

For incidentally found PASH:

• No specific intervention required
• Regular breast cancer screening as per age-appropriate guidelines

Follow-up Recommendations

• For patients managed conservatively (observation):

  • Clinical examination and imaging every 6 months initially 2
  • Return to routine screening if stable for 1-2 years
  • Progression rate of approximately 16-26% has been reported in observation groups 1, 2

• For patients who undergo surgical excision:

  • Routine follow-up as recurrence rate is approximately 13% 2

Important Considerations

• No malignant or premalignant cells directly arising from PASH have been identified after surgical excision of lesions diagnosed as PASH on CNB 1
• The 95% confidence interval for the presence of malignancy in PASH is 0 to 9.4% 5
• PASH may be associated with other breast pathologies:
  • Nonproliferative changes (40%)
  • Proliferative changes without atypia (48%)
  • Rarely associated with malignancy (synchronous but not causative) 3, 4

Pitfalls to Avoid

1. Unnecessary surgical excision: Surgical excision is not routinely needed after PASH diagnosis on CNB unless there are concerning features 1, 5

2. Inadequate sampling: In approximately 35% of cases, PASH may not be detected on initial CNB, requiring surgical excision for definitive diagnosis 2

3. Misdiagnosis: PASH can be histologically confused with angiosarcoma, so expert pathological review is essential 3

4. Overlooking associated pathology: Always evaluate for concurrent breast pathology, as PASH can coexist with other breast conditions 3, 4

By following this evidence-based approach, unnecessary surgical procedures can be avoided while ensuring appropriate management of PASH.