A 55-year-old man comes to the office due to malaise and cough over the past 2 months. He describes yellow sputum production with occasional streaks of blood. The patient smokes a pack of cigarettes daily and has a history of alcohol use disorder with prior episodes of binge drinking. Temperature is 37.1 C (98.8 F). Examination shows poor dentition with dental caries, gingivitis, and enlarged submandibular lymph nodes. Coarse rhonchi are heard during auscultation of the right lung. Chest CT scan reveals an extensive right lung consolidative process with air bronchograms. Bronchoscopy is performed, and a lung biopsy specimen shows the findings in the image below. Which of the following is the most likely diagnosis?

Question

A 55-year-old man comes to the office due to malaise and cough over the past 2 months.  He describes yellow sputum production with occasional streaks of blood.  The patient smokes a pack of cigarettes daily and has a history of alcohol use disorder with prior episodes of binge drinking.  Temperature is 37.1 C (98.8 F).  Examination shows poor dentition with dental caries, gingivitis, and enlarged submandibular lymph nodes.  Coarse rhonchi are heard during auscultation of the right lung.  Chest CT scan reveals an extensive right lung consolidative process with air bronchograms.  Bronchoscopy is performed, and a lung biopsy specimen shows the findings in the image below.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

11ec160b_388b_cd28_9249_5983804340ff_MD0001_00 Actinomycosis is a slowly progressive disease caused by gram-positive anaerobic bacteria. These organisms typically colonize the mouth, colon, and vagina and can be found in dental caries as well as at the margins of gums in patients with poor dentition. Actinomyces infection most frequently leads to the formation of cervicofacial abscesses, but systemic infection can develop anywhere in the body when the mucosa is disrupted. Pulmonary actinomycosis is usually caused by aspiration, which often leads to lower lobe consolidation with air bronchograms (air-filled bronchi with surrounding alveolar opacification). Patients with alcohol use disorder are at increased risk. Diagnosis is made by identifying the bacteria with unique filamentous, branching patterns and the characteristic sulfur granules, which are formed by calcified mycelial fragments. Sulfur granules grossly appear yellow; however, hematoxylin and eosin staining gives them a basophilic (purple/blue) appearance under light microscopy. Penicillin G is the antibiotic treatment of choice. (Choice B) Lung adenocarcinoma frequently affects nonsmokers and can present with cough, hemoptysis, and pulmonary consolidation with air bronchograms. Histopathologic features typically include cuboidal to low columnar hyperchromatic cells with pleomorphism, prominent nucleoli, and glandular differentiation (eg, gland formation, intracellular mucin). (Choice C) Mucor is a ubiquitous fungus naturally found in soil and decaying material. Mucormycosis results when the fungus is inhaled, causing sinopulmonary and sometimes angioinvasive disease, often in patients with diabetic ketoacidosis. Microscopic examination shows broad, ribbon-like, nonseptate hyphae with right-angle branching. (Choice D) Sarcoidosis is an autoimmune disorder characterized by noncaseating granulomas on histopathologic examination of affected areas. (Choice E) Tuberculosis is characterized on histopathology by caseating granulomas, with a necrotic center typically surrounded by multinucleated giant cells. Educational objective: Pulmonary actinomycosis develops most commonly following aspiration and can be confused with lung abscess, malignancy, or tuberculosis. Microscopic findings include filamentous, branching, gram-positive bacteria and sulfur granules. __________ References: Pulmonary actinomycosis during the first decade of 21st century: cases of 94 patients. (http://www.ncbi.nlm.nih.gov/pubmed/23672372) Pulmonary actinomycosis. (http://www.ncbi.nlm.nih.gov/pubmed/12662015)

A 55-Year-Old Man Comes to the Office Due to Malaise