Case Presentation: A 70-year-old female with a history of thyrotoxicosis has had eighteen months of weight loss, dysphagia, cognitive decline, and falls. Six months ago, she had the onset of muscle wasting, most notably in her upper extremities. Then 3 months ago, dysphagia worsened to the point that she started regurgitating food before admission. Finally, she presented to the emergency room due to a one-week history of severe, progressively worsening right lower quadrant abdominal pain and distension. Her imaging showed extensive pneumoperitoneum, which prompted surgery to perform an emergent laparotomy. Three perforations were noted in her colon, and she required a total abdominal colectomy with end ileostomy creation. The neurology service was consulted to evaluate her weakness, dysphagia, and cognitive decline. She had normal levels of creatine kinase, vitamin B1, vitamin B6, folate, ceruloplasmin, anti-double stranded DNA, rheumatoid factor, anti-cyclic citrullinated peptide antibody immunoglobulin G, and free thyroxine. Brain magnetic resonance imaging was normal. Her myositis extended panel was positive for anti-NXP-2 antibody, and antinuclear antibody titer was >1:2560 (homogenous). These lab results, along with her clinical presentation, led to a diagnosis of NXP-2 dermatomyositis. She had none of the classical dermatological manifestations of active cutaneous dermatomyositis. The rheumatology service recommended treatment with monthly intravenous immunoglobulin, and the first doses were administered during this admission. Due to her persistent dysphagia, percutaneous endoscopic gastrostomy tube placement was required during the latter part of her hospitalization. However, during follow-up visits with rheumatology, it was noted that her swallowing function improved, so that she progressed to a pureed diet.
Discussion: Dermatomyositis (DM) encompasses a spectrum of subtypes that may present without the hallmark dermatological features, posing a diagnostic challenge. An astute clinician must consider dermatomyositis when they encounter a patient with significant dysphagia, especially with proximal muscle weakness. Our patient presented with the core features of the anti-NXP2-associated phenotype—profound muscle weakness and progressive dysphagia—but with the addition of a highly critical complication: life-threatening multisite colonic perforation, which has historically been attributed predominantly to the juvenile dermatomyositis population. The anti-NXP2 autoantibody in adult dermatomyositis is a known serological marker associated with severe myositis, peripheral edema, and an increased risk of calcinosis and malignancy.
Conclusions: Given the potentially high fatality rate, risk of recurrence, and potential need for multiple surgical interventions for patients with the anti-NXP2-associated phenotype, prompt recognition and aggressive, targeted immunomodulatory therapy are paramount for restoring gastrointestinal function and preventing catastrophic outcomes. This case underscores the importance of recognizing atypical presentations of DM to guide timely diagnosis and prevent catastrophic complications.