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M ycobacterium chelonae, a nontuberculosis (atypical) Mycobacterium, is a rare cause of postoperative cutaneous infections in immunocompetent patients. In the postoperative setting, cutaneous atypical mycobacterial infections can present similarly to suture reactions and malignancy recurrence. Distinguishing cutaneous atypical mycobacterial infections from clinical mimickers profoundly affects management. We present a case of a cutaneous M. chelonae infection after Mohs micrographic surgery for squamous cell carcinoma. Recognizing and appropriately treating cutaneous atypical mycobacterial infections is important; inadequately treated lesions can spread to underlying soft tissue and bone and can rarely disseminate to internal organs. A 69-year-old healthy woman underwent Mohs micrographic surgery for a squamous cell carcinoma of the right hand repaired with a primary layered linear closure using subcutaneous 4-0 poliglecaprone and superficial 5-0 polypropylene sutures. Six weeks postoperatively, she presented with an erythematous papule at the distal wound edge. The papule was treated as a possible suture reaction to poliglecaprone and was injected with 0.1 mL of 10 mg/ mL intralesional triamcinolone with resolution. Three-anda-half months postoperatively, she developed 3 tender erythematous papules coalescing into a plaque on the proximal scar. The new lesion was initially also believed to be a suture reaction and was injected with 0.15 mL of 10 mg/mL intralesional triamcinolone. Doxycycline was started for anti-inflammatory properties. She showed no improvement after 2 weeks, so a biopsy was performed (Figure 1). Pathology showed granulomatous inflammation with elongated rod-like organisms, and Fite staining was strongly positive (Figure 2). Acid-fast bacteria tissue culture was positive for M. chelonae, believed to be secondary to tap water exposure during wound care in the postoperative period. The lesion was excised and healed without complications. Infectious disease was also consulted and recommended clarithromycin. Patient deferred this treatment course but has had no clinical evidence of recurrence at 5 months (Figure 3A, B). Mycobacterium chelonae is classified as a rapidly growing Mycobacterium (RGM) along with M. fortuitum and M. abscessus. Rapidly growing mycobacteria are environmental saprophytes found in water (including tap water), soil, dust, and animals. Given the ubiquitous nature of RGMs, inoculation of postsurgical wounds can be difficult to prevent. In addition, as in this patient, RGM infections often begin as asymptomatic, benign-appearing lesions and patients may delay seeking care. A 2006 study reported a median delay in diagnosis of cutaneous atypical mycobacterial infections of 86 days, which can be attributed in part to the indolent nature and often subtle presentation of cutaneous atypical mycobacterial infections. As such, a high index of suspicion is needed to accurately diagnose cutaneous atypical mycobacterial infections, particularly with nonhealing, tender postoperative nodules and plaques, as was seen in this patient. Cutaneous M. chelonae infections are seen in immunocompromised patients, particularly those with defects in the IL-12/IFN-g axis and GATA2 deficiencies or in immunocompetent patients after surgical procedures or traumatic innoculation. Mycobacterium chelonae infections have been described after multiple dermatologic surgical and cosmetic procedures, including Mohs micrographic surgery, laser resurfacing, botulinum toxin injections, hair transplant, liposuction, tattooing, body piercing, and Figure 1. Right hand, 4 months post-Mohs micrographic surgery.