Cutaneous metastases mimicking hidradenitis suppurativa: a diagnostic challenge.

Background: Hidradenitis suppurativa (HS) is a chronic, recurrent, and debilitating inflammatory condition characterized by abscesses, comedones, and nodules. The heterogeneous presentation of HS often leads to diagnostic challenges, with clinical mimics such as cutaneous metastases (CMs) being of particular importance. CMs can present as initial manifestations of metastatic disease, necessitating accurate identification to guide potentially lifesaving treatment. However, the diagnostic and therapeutic approaches for HS and CMs differ significantly, underscoring the need for prompt and accurate differentiation.

Case report: This report presents 3 cases of primary malignancies in which CMs mimicked HS. Case 1 had diffuse large B-cell lymphoma; case 2 had a history of right breast atypical ductal hyperplasia and borderline low-grade ductal carcinoma in situ, along with triple-negative invasive ductal carcinoma of the left breast with extensive metastasis to the iliac bone and lung; and case 3 had invasive mammary carcinoma of the right breast with axillary lymph node involvement. All 3 patients presented with nodular lesions resembling HS, but further investigation, including molecular testing, confirmed the diagnosis of CMs.

Conclusion: The clinical overlap between HS and CMs, which can present with similar features such as nodules, abscesses, and draining lesions, underscores the critical importance of distinguishing these entities. Despite their similar clinical appearance, HS and CMs have vastly different management protocols. Accurate diagnosis of CMs enables timely and appropriate intervention, which in turn aids in optimizing clinical outcomes and ensuring the use of effective treatment strategies for affected patients.