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THE EFFECTS OF CHRONIC SMOKING: AN UNUSUAL CASE OF SQUAMOUS METAPLASIA OF THE LACTIFEROUS DUCTS (SMOLD)

      TOPIC: Tobacco Cessation and Prevention
      TYPE: Medical Student/Resident Case Reports
      INTRODUCTION: Squamous metaplasia of the lactiferous ducts (SMOLD) is an uncommon condition that is characterized by the abnormal keratinization of the lactiferous ducts' cuboidal epithelium [1]. It is associated with smoking and vitamin A deficiency. Patients often complain of an unusual breast mass and vague chest discomfort. Here we present the case of a 61-year-old man recently diagnosed with SMOLD.
      CASE PRESENTATION: A 61-year old male with a past medical history of uncontrolled hypertension, hyperlipidemia and diabetes presented to the hospital with severe right-sided chest pain for the past one day. He endorsed a 30-pack years smoking history. Vitals on presentation were significant for a blood pressure of 160/90 mmHg, heart rate 73 bpm, temperature of 98.2 F, and an oxygen saturation of 92% on ambient air. Physical examination was significant for a tender right periareolar mass and and right nipple serosanguinous discharge. Electrocardiogram showed sinus rhythm with no dynamic ST changes. Echocardiogram revealed a normal ejection fraction with mild aortic insufficiency and mild mitral regurgitation. Troponin levels were negative. A mammogram revealed a right breast mass with irregular borders (Figure 1). Right-sided breast ultrasound showed a 0.5 cm mass and abnormal appearing axillary lymph nodes with a reading of Bi-RADS 5 (Figure 2). Before a core biopsy was obtained, the patient was started on amoxicillin-clavulanate for presumed mastitis. Immunohistological analysis of the affected breast's tissue confirmed SMOLD. Antibiotics were discontinued and the patient was then referred to general surgery for surgical resection.
      DISCUSSION: The rare occurrence of SMOLD has resulted in limited knowledge about its etiology. However, it has been associated with smoking cigarettes, as the overwhelming majority of SMOLD patients are chronic smokers. Smoking induces vitamin A deficiency, which in turn causes squamous metaplasia and abnormal epidermalization of the lactiferous ducts [2,3]. Since SMOLD can mimic the symptoms of a bacterial abscess, many patients are unnecessarily subjected to long and ineffective antibiotic courses. The appropriate curative treatment would be the resection of the plugged/ruptured lactiferous duct, which would halt disease progression. Cessation of smoking will not only decrease the risk of developing this painful disorder, but it will also decrease the risk of developing more serious pathologies, such as lung, breast, liver and colorectal cancer.
      CONCLUSIONS: SMOLD is a rare breast condition which needs to be kept in mind whenever a chronic smoker complains of breast pain with areolar discharge. In addition to surgical resection, patients should also be encouraged to quit smoking, as it will improve life expectancy.
      REFERENCE #1: Dillon DA, Lester SC. Lesions of the Nipple. Surg Pathol Clin. 2009;2(2):391-412. doi:10.1016/j.path.2009.02.010
      REFERENCE #2: Febres-Aldana CA, Alvarez Moreno JC, Rivera M, Kaplan S, Paramo J, Poppiti R. Understanding the histogenesis of a HRAS-PIK3R1 co-driven metastatic metaplastic breast carcinoma associated with squamous metaplasia of lactiferous ducts. Pathol Int. 2020;70(2):101-107. doi:10.1111/pin.12887
      REFERENCE #3: Lo G, Dessauvagie B, Sterrett G, Bourke AG. Squamous metaplasia of lactiferous ducts (SMOLD). Clin Radiol. 2012;67(11):e42-e46. doi:10.1016/j.crad.2012.07.011
      DISCLOSURES: No relevant relationships by Jonathan Ariyaratnam, source=Web Response
      No relevant relationships by Ian Landry, source=Web Response
      No relevant relationships by Vikram Sumbly, source=Web Response
      No relevant relationships by Theo Trandafirescu, source=Web Response