What is the next course of action for a painful and recurrent tumor, measuring 2 by 5 by 0.5 mm, on the proximal deltoid?

Management of Painful Recurrent Proximal Deltoid Tumor

For a painful and recurrent tumor measuring 2 x 5 x 0.5 mm on the proximal deltoid, you should proceed with wide local excision achieving 1-2 cm negative margins, performed by a surgeon trained in soft tissue tumor management, with mandatory excision of any previous biopsy tract or scar en bloc with the tumor. 1

Immediate Surgical Approach

Wide local excision is the cornerstone of treatment for recurrent soft tissue tumors in this location, with the goal of achieving negative surgical margins of at least 1-2 cm. 1 The small size (2 x 5 x 0.5 mm) makes complete excision with adequate margins technically feasible without major functional sacrifice in the deltoid region.

Critical Surgical Considerations

• Any previous biopsy tract and cutaneous scar must be excised en bloc with the tumor to prevent seeding and reduce recurrence risk 1
• Re-operation at a reference center is mandatory if initial resection yields R1 (microscopically positive) or R2 (grossly positive) margins, provided adequate margins can be achieved without major morbidity 1
• The deltoid can be safely preserved during proximal humerus region resections when a continuous fat rim separates the tumor from the muscle on MRI, the tumor is small, and the axillary nerve can be identified 2

Adjuvant Radiotherapy Decision-Making

Adjuvant radiotherapy is generally NOT required after complete excision with negative margins for low-grade tumors, but specific anatomical and histological factors must guide this decision 1

When to Consider Radiotherapy

• For recurrent tumors after incomplete surgical resection, adjuvant radiotherapy may reduce the risk of further recurrence, particularly when re-resection would cause unacceptable morbidity 3
• If radiotherapy is indicated, use intensity-modulated radiotherapy (IMRT) with image-guided radiotherapy (IGRT) techniques at 50-60 Gy in 1.8-2 Gy fractions, with possible boosts up to 66 Gy 3
• Coregistration with contrast-enhanced MRI sequences in treatment position is imperative for optimal targeting 3

Follow-Up Protocol

Patients require intensive surveillance given the recurrent nature of this tumor:

• Clinical examination and history every 3 months 1
• MRI of the resection site twice yearly for the first 2-3 years, then annually 1
• Document exact size, location, and relationship to previous surgical site at each visit 4
• Evaluate for skin changes, fixation to underlying structures, or regional lymphadenopathy 4

Differential Diagnosis Considerations

While proceeding with surgical excision, the differential diagnosis for a recurrent deltoid tumor includes:

• Desmoid-type fibromatosis (aggressive fibromatosis): These tumors have high local recurrence rates (12-65% after intralesional curettage, 0-12% after wide excision) and require aggressive surgical margins 3, 5, 6
• Calcified leiomyoma: Rare in the deltoid but can present as a painful mass; requires adequate margin excision to prevent recurrence 7
• Intramuscular lipoma: Unusual in the deltoid but presents as a palpable soft mass, typically with pain on abduction and extension 8

Critical Pitfalls to Avoid

• Do not assume the recurrent tumor is benign scar tissue—tissue diagnosis through excision is mandatory for any recurrent mass in a patient with prior tumor history 4
• Avoid inadequate margins: The most common cause of recurrence in soft tissue tumors is incomplete initial excision 1
• Do not inject corticosteroids into the deltoid area for pain management, as this site has a significantly higher incidence of local atrophy and should be avoided in favor of the gluteal area 9
• Ensure adequate tissue sampling if biopsy is performed pre-operatively, obtaining sufficient material for histology and any necessary molecular testing 4

Pain Management During Surveillance

If observation is considered before definitive surgery (though not recommended for recurrent disease):

• Non-steroidal anti-inflammatory drugs (NSAIDs) can be used for symptomatic relief 3
• Avoid local corticosteroid injection in the deltoid due to high risk of atrophy 9

The recurrent nature of this tumor, combined with associated pain, makes immediate surgical excision with adequate margins the most appropriate next step rather than observation or medical management.