Snapshot A 4-year-old boy presents to the pediatrician by his mother due to noting a lump under his mandible. She first noticed the lump approximately 2 weeks ago and it has progressively increased in size. On physical exam, the patient does not appear to be in any acute distress. There is a 2-3 cm, nontender mass with parchment-like skin overlying the mass. The mass is drained and cultures and a polymerase chain reaction are sent of the mass. (Superficial lymphadenitis likely caused by MAC) Introduction Definition login to view 13 more bullets Nontuberculous Mycobacterium Disease Clinical Presentation Making the Diagnosis Comments Pulmonary disease Symptoms are typically non-specific and depend if the patient has underlying pulmonary disease: patients with underlying pulmonary disease typically present similar to tuberculosis (e.g., cough, weight loss, upper lobe infiltrates, and cavities) Symptoms include: cough (dry or productive) fatigue malaise dyspnea weakness Based and clinical and radiographic findings (e.g., nodular or cavitary opacities or multifocal bronchiectasis) Sputum acid-fast bacilli and culture Lung biopsy with mycobacterial histopathologic features (granulomatous inflammation or acid fact bacillus), if needed -- Superficial lymphadenitis Enlarged lymph nodes most commonly the cervicofacial node in children nontender and unilateral enlarges over the course of weeks Culture or polymerase chain reaction (PCR) of the fistula drainage, tissue, or caseous material Most commonly affects children < 5 years of age Disseminated disease Fever Fatigue Malaise Anorexia Sequelae of organ involvement: bone marrow (neutropenia and anemia) hepatosplenomegaly Blood cultures of the mycobacterium Risk factors include advanced HIV infection hematologic malignancy tumor necrosis alpha inhibitors or other immunosuppressive agents Skin and soft tissue infection Skin lesion erythematous or bluish papule or nodule at the site of abrasion lymphadenopathy may be present Culture or PCR of the lesion Fisherman or people who work at aquariums are at risk of developing M. marinum infection Epidemiology Incidence login to view 3 more bullets Treatment Medical login to view 6 more bullets Complications Dissemination of the nontuberculous mycobacterium can occur in severely immunocompromised patients