Coalescing Papules on Bilateral Mastectomy Scars

The Diagnosis: Scar Sarcoidosis

Although scars on both breasts were involved, the decision was made to biopsy the right breast because the patient reported more pain on the left breast. Biopsy showed noncaseating granulomas consistent with scar sarcoidosis (Figure). Additional screening tests were performed to evaluate for any systemic involvement of sarcoidosis, including a complete blood cell count, comprehensive metabolic panel, angiotensin-converting enzyme level, tuberculosis serology screening, electrocardiogram, chest radiograph, and pulmonary function tests. She also was referred to rheumatology and ophthalmology for consultation. The results of all screenings were within reference range, and no sign of systemic sarcoidosis was found. She was treated with hydrocortisone ointment 2.5% for several weeks without notable improvement. She elected not to pursue any additional treatment and to monitor the symptoms with close follow-up only. One year after the initial visit, the skin lesions spontaneously and notably improved.

Biopsy of the right breast showed noncaseating granulomas consistent with scar sarcoidosis (H&E, original magnification ×100).

Sarcoidosis is a systemic granulomatous disorder of unknown etiology that most commonly affects the lungs. It also can involve the lymph nodes, liver, spleen, bones, gastrointestinal tract, eyes, and skin. Cutaneous sarcoidosis has been documented in the literature since the late 1800s and occurs in up to one-third of sarcoid patients.¹ Cutaneous lesions developing within a preexisting scar is a well-known variant, occurring in 29% of patients with cutaneous sarcoidosis in one clinical study (N=818).² There have been many reports describing scar sarcoidosis, with its development at prior sites of surgery, trauma, acne, or venipuncture.³ Other case reports have described variants of scar sarcoidosis developing at sites of hyaluronic acid injection, laser surgery, ritual scarification, tattoos, and desensitization injections, as well as prior herpes zoster infections.^4-9

Cutaneous sarcoidosis has a wide range of clinical presentations. Lesions can be described as specific or nonspecific. Specific lesions demonstrate the typical sarcoid granuloma on histology and more often are seen in chronic disease, while nonspecific lesions more often are seen in acute disease.^3,10 Scar sarcoidosis is an example of a specific lesion in which old scars become infiltrated with noncaseating granulomas. The granulomas typically are in the superficial dermis but may involve the full thickness of the dermis, extending into the subcutaneous tissue.¹¹ The cause of granulomas developing in scars is unknown. Prior contamination of the scar with foreign material, possibly at the time of the trauma, is a possible underlying cause.¹²

Typical scar sarcoidosis presents as swollen, erythematous, indurated lesions with a purple-red hue that may become brown.^3,12 Tenderness or pruritus also may be present.¹³ Interestingly, our patient's scar sarcoidosis presented with a yellow hue at both mastectomy sites.

Diagnosing scar sarcoidosis can be challenging. Patients are diagnosed with sarcoidosis when a compatible clinical or radiologic picture is present along with histologic evidence of a noncaseating granuloma and other potential causes are excluded.¹¹ The differential includes an infectious etiology, other types of granulomatous dermatitis, hypertrophic scar, keloid, or foreign body granuloma.

Scar sarcoidosis can be isolated in occurrence. It also can precede or occur concomitantly or during a relapse of systemic sarcoidosis.¹⁰ Most commonly, patients with scar sarcoidosis also have systemic manifestations of sarcoidosis, and changing scars may be an indicator of disease exacerbation or relapse.¹⁰ For patients who only demonstrate specific skin lesions of cutaneous sarcoidosis, approximately 30% develop systemic involvement later in life.³ For this reason, close monitoring and regular follow-up are necessary.

Treatment of scar sarcoidosis is dependent on the extent of the disease and presence of systemic sarcoidosis. Topical and systemic corticosteroids, hydroxychloroquine, chloroquine phosphate, and methotrexate all have been shown to be helpful in treating cutaneous sarcoidosis.³ For scar sarcoidosis that is limited to only the scar site, as seen in our case, monitoring and close follow-up is acceptable. Topical steroids can be prescribed for symptomatic relief. Scar sarcoidosis can resolve slowly and spontaneously over time.¹⁰ Our patient notably improved 1 year after the initial presentation without treatment.

Scar sarcoidosis is a well-documented variant of cutaneous sarcoidosis that can have important implications for diagnosing systemic sarcoidosis. Although there are typical lesions that represent scar sarcoidosis, it is important to have a high degree of suspicion with any changing scar. Once diagnosed through biopsy, a thorough investigation for systemic signs of sarcoidosis needs to be performed to guide treatment.