What is the next step in management for a 35-year-old male patient who presented with a resolved lump in his left axilla (armpit), initially thought to be an ingrown hair?

Management of a Resolved Axillary Lump

No further workup is needed for a resolved ingrown hair in the axilla that has completely disappeared on clinical examination. 1

Clinical Assessment

When evaluating a patient with a history of an axillary lump that has resolved, the following factors should be considered:

• Complete resolution of the lump
• Patient's age and risk factors
• Initial presentation characteristics
• Associated symptoms

In this case, the 35-year-old male patient presented with a history of a lump in the left axilla that was attributed to an ingrown hair and has completely resolved. This presentation is consistent with a benign, self-limiting condition.

Evidence-Based Approach

According to the ACR Appropriateness Criteria for Imaging of the Axilla, when evaluating axillary lumps, the initial approach depends on the clinical presentation 1. For a palpable axillary lump, ultrasound is typically the first-line imaging modality. However, when a lump has completely resolved and had a clear benign etiology (ingrown hair), no further imaging is warranted.

The differential diagnosis for axillary lumps includes:

• Benign etiologies (most common):
  • Reactive lymph nodes
  • Infection
  • Ingrown hairs
  • Sebaceous cysts
• Malignant etiologies (less common):
  • Breast cancer metastasis
  • Lymphoma
  • Other metastatic disease

Management Algorithm

1. For completely resolved axillary lumps with clear benign etiology:

   • No further workup needed
   • Patient education about normal lymph nodes and when to seek care

2. For recurrent or persistent axillary lumps:

   • Ultrasound examination of the axilla 1
   • Consider mammography if breast cancer is suspected

3. For suspicious features (even if temporarily resolved):

   • Enlarging mass
   • Constitutional symptoms
   • Personal history of cancer
   • Abnormal imaging findings → Proceed to imaging and possible biopsy

Patient Education

The patient should be informed about:

• The benign nature of resolved ingrown hairs
• Signs that would warrant return evaluation:
  • Recurrence of the lump
  • Growth of any new lumps
  • Associated symptoms like pain, redness, or drainage
  • Constitutional symptoms (fever, weight loss)

Common Pitfalls to Avoid

1. Overinvestigation: Performing unnecessary imaging for clearly benign, self-limited conditions increases healthcare costs and patient anxiety.

2. Underinvestigation: Failing to follow up on persistent or recurrent lumps, especially in patients with risk factors.

3. Poor documentation: Ensure clear documentation of the resolved nature of the lump and patient education provided.

In this case, since the axillary lump was identified as an ingrown hair and has completely resolved, routine clinical follow-up is appropriate without the need for additional imaging or intervention. The patient should be instructed to return if the lump recurs or if new concerning symptoms develop.