Systematic review of giant gastric lipomas reported since 1980 and report of two new cases in a review of 117110 esophagogastroduodenoscopies

Table 3 Distinctive features of giant gastric lipomas

Test/technique/parameter	Distinctive characteristic	Pathophysiology	Ref.
Age	Average age = 54.5 ± 17.0 years old		Current Report
Gender ratio	Male-to-Female ratio approximately 2:1	Unknown (sexual hormones?)	Current Report
Lipoma size	Average maximal dimension = 7.9 cm × 4.1 cm		Current Report
Most common clinical presentation	19 of 32 presented with acute UGI bleeding	Postulated from ulcer at tip of lipoma caused by rubbing/trauma of tip against gastric wall contralateral to base of lipoma	Current Report
EGD	Smooth bulge covered by normal mucosa	Submucosal (or occasionally subserosal) location. No tumor invading mucosa due to benignity	Neto et al[22], 2012, Thompson et al[36], 2003
	Most commonly located in gastric antrum		Thompson et al[36], 2003, Menon et al[40], 2014
	Yellowish hue	Yellow color of adipose tissue in submucosa transmitted to mucosal surface	Menon et al[40], 2014, Chen et al[41], 2014
	Broad base	Rarely pedunculated	Singh et al[18], 1987
	Cushion or pillow sign: easily deforms like a cushion with mild pressure applied against it by an endoscopic probe (closed biopsy forceps).	Lipoma consists of soft, compressible tissue.	De Beer et al[37], 1975, Hwang et al[38], 2005
	Tenting sign: Mucosa easily retracts after it is grasped and gently pulled with a forceps	Mucosa separates from submucosa when gently pulled via forceps because lipoma has fibrous capsule and does not infiltrate into adjacent tissue	Priyadarshi et al[14], 2015
	Naked fat sign: repeated biopsies at same site reveals yellow fatty tissue	Multiple biopsies at same site (using well technique) exposes submucosal lipomatous tissue	Chen et al[41], 2014, Patrick et al[42], 2007
	Moderately frequent focal central ulceration of mucosa	Likely secondary to giant lipoma abutting and rubbing against contralateral gastric wall. Ischemia may also contribute to ulceration.	Kumar, et al[8], 2015, Thompson et al[36], 2003
Highly useful diagnostic test for lipomas	Typically strongly suggestive of diagnosis	Demonstrates anatomy of mass. Shows if ulcerated or intussuscepting mass. Characteristic findings: yellow hue, smooth overlying mucosa, relatively homogeneous, round margins. Exhibits pillow, tenting or naked fat signs.	Current Report
Endoscopic biopsies	Standard endoscopic biopsies usually reveal only normal mucosa and insensitive for pathologic diagnosis.	Standard endoscopic biopsies typically sample superficial mucosa and miss deeper submucosal lipoma.	Current Report, Neto et al[22], 2012
	Techniques to increase yield of endoscopic biopsies; use jumbo forceps for endoscopic biopsies; or well technique (repeated endoscopic biopsies at same mucosal site).	Repeated biopsies at same site permits sampling of deeper (submucosal) tissue	Wang et al[47], 2015
Abdominal CT	Submucosal mass	Typically submucosal, occasionally subserosal, and never mucosal.	Beck et al[3], 1997
	Well-circumscribed with well-defined edges	Characteristically has a firm fibrous capsule with no invasion through capsule due to benignity	Thompson et al[36], 2003
	Typically solitary	Multiple gastric lipomas are very rare	Park et al[48], 1999, Skinner, et al[49], 1983
	Homogeneous	Composed of homogeneous lipocytes	Park et al[48], 1999, Alkhatib et al[50], 2012
	Densitometry of -80 to -120 HU (Hounsfield units).	Characteristic of adipose tissue	Alberti et al[20], 1999
Highly useful as diagnostic test for gastric lipomas	Demonstrates characteristic findings in about 95% of cases.	Characteristic findings: well-circumscribed, submucosal, homogeneous mass with an attenuation characteristic of fat.	Current Report
EUS	In third layer of gastric wall	Typically submucosal (rarely subserosal)	Chen et al[43], 2011
	Hyperechoic (bright)		Alkhatib et al[50], 2012, Eckardt et al[51], 2012
EUS-guided needle biopsy or endoscopic mucosal resection	EUS guidance used to obtain diagnostic deep (submucosal) biopsies	Deep biopsies permit sampling of submucosal lipomas	Alkhatib et al[50], 2012, Karaca et al[52], 2010
Transcutaneous abdominal ultrasound	Not very useful for gastric lipomas.	Supplaned by abdominal CT or EUS for evaluating suspected gastric lipomas	Current Report
Upper gastrointestinal series	Mostly obsolete test	CT is a superior alternative	Current Report
Histopathology	Diagnostic features	Rounded, plump cells with abundant clear, homogeneous cytoplasm containing fat, eccentric nuclei, mature adipocytes with no lipoblasts, scant stroma, rare inflammatory cells.	Current Report
Imunohistochemistry	Reveals no MDM2 or CDK4 gene amplification.	Distinguishes lipoma from liposarcoma.	Shimada et al[45], 2006, Boltze et al[46], 2001
Immunohistochemistry	Lipoma stains positively for CD4	Indicates spindle-cell lipoma variant	Lau et al[39], 2015

UGI: Upper gastrointestinal; EGD: Esophagogastroduodenoscopy; CT: Computerized tomography; EUS: Endoscopic ultrasound.