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

Management of Focal Pseudoangiomatous Stromal Hyperplasia (PASH)

Core needle biopsy is sufficient to confirm PASH when imaging findings are benign, and surgical excision is not mandatory to rule out malignancy after a confirmed PASH diagnosis. 1

Initial Diagnostic Approach

When to Perform Core Needle Biopsy

• Perform core needle biopsy for any palpable mass or suspicious imaging finding to establish diagnosis 1, 2
• Core biopsy successfully confirms PASH in 63-65% of cases 1, 2
• The remaining 35% with negative or inconclusive core biopsy require surgical excision for definitive diagnosis 2

Imaging Characteristics

• PASH demonstrates no specific radiologic features that distinguish it from other benign breast lesions 1, 3
• Clinically, PASH typically presents as a firm mass often misdiagnosed as fibroadenoma 4
• Lesions range from 0.3 cm to 7.0 cm in size 5

Treatment Algorithm Based on Clinical Presentation

For PASH Confirmed on Core Needle Biopsy with Benign Imaging

• Observation with close surveillance is appropriate 1
• Follow-up imaging at 6-month intervals 2
• No surgical excision is necessary to exclude occult malignancy 1

Indications for Mandatory Surgical Excision

• Lesions >3 cm in size 1
• Progressive growth of the lesion on serial imaging 1, 2
• Suspicious radiologic features despite benign core biopsy 2, 3
• Inconclusive or negative core biopsy when clinical suspicion remains 2, 3
• Palpable masses with median size >3.1 cm 3

Surgical Technique When Excision is Performed

• Simple local excision is adequate treatment 4
• Complete excision is preferred, though incomplete excision may spontaneously regress 4
• Diffuse bilateral PASH rarely may necessitate mastectomy 4

Recurrence and Surveillance

Recurrence Rates

• Observation without excision: 26% progression rate 2
• After surgical excision: 13% recurrence rate 2
• Ipsilateral recurrence occurs in approximately 12.5% of cases (5 of 40 patients) 4
• Contralateral PASH develops in 5% of cases 4

Long-term Monitoring Strategy

• Close surveillance is mandatory given recurrence rates of 13-26% 2
• Continue follow-up regardless of initial treatment choice 2
• Monitor for new masses or growth in existing lesions 1

Associated Pathology and Cancer Risk

Concurrent Findings

• 30% of patients have synchronous cancer or carcinoma in-situ at or before PASH diagnosis 2
• Associated benign findings include nonproliferative changes (40%), proliferative changes without atypia (49%), atypical ductal or lobular hyperplasia 3, 5
• Rare associations with phyllodes tumor, in situ carcinoma, or invasive cancer 3

Critical Pitfall

• PASH itself does not transform into malignancy, but concurrent malignant or premalignant lesions are common 1, 2
• Always evaluate the entire breast for synchronous pathology 2, 3

Patient Demographics and Hormonal Factors

• Predominantly affects premenopausal and perimenopausal women (median age 41-45 years) 1, 5
• 95% of cases are ER or PR positive, suggesting hormonal etiology 5
• Rare cases occur in males with gynecomastia or transgender males on hormone therapy 3, 5

Key Management Principles

For lesions ≤3 cm with benign imaging and confirmed PASH on core biopsy: Observation with 6-month interval imaging 1, 2

For lesions >3 cm, growing lesions, or suspicious features: Surgical excision regardless of core biopsy results 1, 3

For inconclusive core biopsy: Proceed directly to surgical excision rather than repeat biopsy 2, 3