Soft tissue
Adipose tissue
Lipoblastoma / lipoblastomatosis

Author: Vijay Shankar, M.D. (see Authors page)

Revised: 8 August 2016, last major update August 2012

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Lipoblastoma / lipoblastomatosis

Definition / General
  • Lobulated tumor, either localized (lipoblastoma) or diffuse (lipoblastomatosis), resembling fetal adipose tissue
Terminology
  • Lipoblastoma: also called fetal/embryonal lipoblastoma; well circumscribed and subcutaneous
  • Lipoblastomatosis: deep-seated and ill-defined
Epidemiology
  • Rare
  • Infants and young children age 3 years or less (rarely ages 14 - 24 years)
  • 80% are boys
Sites
  • Extremities, trunk, head and neck
  • Occasionally mediastinum, retroperitoneum or inguinal region, thigh, parotid region, scrotum, intrathoracic region
Clinical Features
  • Usually presents as painless superficial soft tissue mass, 75% on left side
  • If not removed, matures into lipoma but with prominent fibrous septa
  • FISH is helpful to confirm diagnosis (Histopathology 2008;52:294)
Case Reports
Treatment
Clinical Images

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Lobulated and encapsulated tumor

Gross Images

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Courtesy of Mark R. Wick, M.D.



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Large white mass

Micro Description
  • Hypocellular lobules of adipocytes in various stages of differentiation including preadipocytes (spindle or stellate shaped), uni- or multi-vacuolated lipoblasts and mature adipocytes in central lobule
  • Separated by prominent fibrous septa that may be cellular
  • Has plexiform vascular pattern and abundant myxoid stroma
  • May have prominent extracellular mucinous pools
  • Resembles fetal fat and myxoid liposarcoma
  • Lipoblastomatosis: less lobulation; infiltrates skeletal muscle
Micro Images

Images hosted on PathOut servers:

Courtesy of Mark R. Wick, M.D.



Lobular architecture with prominent fibrous septa

Plexiform vascular pattern with myxoid matrix and small fat cells

Resembles lipoma with minimal myxoid stroma

1 year old boy with neck mass



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Various images

Scrotal tumor

Scapula tumor

Cytology Description
  • Moderate to poorly cellular
  • Clusters of lipocytes, lipoblasts, spindle cells
  • Background of myxoid material and naked oval nuclei (Diagn Cytopathol 2005;33:195)
Cytology Images

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1 year old boy with neck mass

Electron Microscopy Description
  • Cells have investing basal lamina, pinocytotic vesicles, Golgi membranes, round / oval mitochondria, cytoplasmic glycogen and cytoplasmic lipid (Am J Surg Pathol 1980;4:163)
  • Resembles myxoid liposarcoma and normal developing fat
Electron Microscopy Images

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High nuclear-cytoplasmic ratio

Molecular / Cytogenetics Description
Molecular / Cytogenetics Images

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FISH / CISH of PLAG1 gene

Differential Diagnosis
Additional References