A Systematic Review of Paradoxical Adipose Hyperplasia (PAH) Post-Cryolipolysis

January 2017 | Volume 16 | Issue 1 | Original Article | 62 | Copyright © January 2017

Derek Ho BSa,b and Jared Jagdeo MD MSa,b,c

aSacramento VA Medical Center, Mather, CA bUniversity of California Davis, Sacramento, CA cState University of New York Downstate Medical Center, Brooklyn, NY

BACKGROUND: Body sculpting, or body contouring, is among the fastest growing areas in cosmetic dermatology. Cryolipolysis, or “fat freezing,” was FDA-cleared (CoolSculpting System, ZELTIQ Aesthetics, Pleasanton, CA) initially in 2010 for fat removal of the anks, and subsequently received FDA-clearance for other anatomical locations. Over the past several years, there have been increasing published reports and physician discussion regarding paradoxical adipose hyperplasia (PAH) post-cryolipolysis, previously identified as a “rare” adverse effect. OBJECTIVE: To review published reports of PAH post-cryolipolysis, expand on previously proposed hypothesis of PAH, and provide rec- ommendations for prevention and treatment of PAH. METHODS AND MATERIALS: On July 26, 2016, we systematically searched the computerized medical bibliographic databases PubMed, EMBASE, Web of Science, and CINAHL with the search term “cryolipolysis.” RESULTS: A total of 314 records were returned from our search terms and 10 records were found to be suitable for our review. We identi- ed a total of 16 cases of PAH post-cryolipolysis in the published literature. CONCLUSIONS: Based upon the published literature, we identi ed that the current incidence of PAH may be higher than previously re- ported. Although the pathoetiology of PAH is currently unknown, we hypothesize that some adipocytes may be “naturally selected” for survival due to their inherent tolerance to cryolipolysis. We believe that while cryolipolysis is an effective non-invasive treatment option for body contouring, physicians and patients should be aware of PAH as a potential adverse effect and treatment options. J Drugs Dermatol. 2017;16(1):62-67.


Body sculpting, or body conturing, is among the fastest growing areas in cosmetic dermatology. In 2015, dermatologic surgeons performed over 230,000 body sculpting treatments.1 One survey reported 89% of consumers, are concerned with excess weight and 35% of consumers are considering body sculpting treatments.2 In addition to the common indication of body sculpting for removal of excess lower abdominal fat for men and women, men are also concerned with pseudogynecomastia (enlarged male breast due to excess fat) and procedures for male breast reduction rose 26% from 2014 to 2015.2 Pseudogynecomastia and excess lower abdominal fat may affect patients' quality-of-life, resulting in self-consciousness and psychological distress.3 Liposuction is the most popular and the most effective surgical treatment for focal fat reduction.4 However, liposuction is associated with possible adverse effects and downtime. Concerns associated with invasive procedures, such as liposuction, include risks for infection, nerve damage, hematoma, complications with anesthesia, and the high cost associated with surgical treatment. Physicians and consumers alike are seeking minimally invasive, low risk, and cost-effective techniques for focal fat reduction with fast recovery time.Recently, non-invasive fat reducation techniques have become more widely available and may be associated with fewer adverse effects compared to invasive procedures. Non-invasive fat reduction techniques include using temperature, sound and light modulation to selectively target adipocytes for fat removal while minimizing the effects on the epidermis and dermis.5 Examples include cryolipolysis, high intensity focused ultrasound, and low level and infrared lasers using wavelengths specifically targeted for adipocytes.5,6 A landmark manuscript published in 2008 reported that pro- longed, controlled local skin cooling can induce selective damage and removal of fat deposits without injuring local tissue.7 This reported phenomenon is based upon historical observations that lipid-rich tissue is more susceptible to cold injury than surrounding water-rich tissue.8 Cryolipolysis, or  "fat freezing," was FDA-cleared (CoolSculpting System, ZELTIQ Aesthetics, Pleasanton, CA) for fat removal of the anks or "love handles" (K080521) in 2010, abdomen (K120023) in 2012, thighs (K133212) in 2014, submental region (K151179) in 2015, and arms (K162050), bra bulge, back, and underneath the buttock or "banana roll" (K160259) in 2016.