Determining residual adipose tissue characteristics with MRI in patients with various subtypes of lipodystrophy

Abstract

Purpose: We aimed to investigate residual adipose tissue with whole-body magnetic resonance imaging to differentiate between subtypes of lipodystrophy.

Methods: A total of 32 patients (12 with congenital generalized lipodystrophy [CGL], 1 with acquired generalized lipodystrophy [AGL], 12 with familial partial lipodystrophy [FPLD], and 7 with acquired partial lipodystrophy [APL]) were included.

Results: Despite generalized loss of metabolically active adipose tissue, patients with CGL1 caused by AGPAT2 mutations had a significant amount of residual adipose tissue in the scalp, earlobes, retro-orbital region, and palms and soles. No residual adipose tissue was noted particularly in the head and neck, palms and soles in CGL2 caused by BSCL2 mutations. CGL4 caused by mutations in the PTRF gene was characterized with well-preserved retro-orbital and bone marrow fat in the absence of any visible residual adipose tissue in other areas. No residual adipose tissue was observed in AGL. Despite loss of subcutaneous fat, periarticular adipose tissue was preserved in the lower limbs of patients with FPLD. Retro-orbital adipose tissue was surprisingly preserved in APL, although they lacked head and neck fat.

Conclusion: Lipodystrophies are a heterogeneous group of disorders characterized by generalized or partial loss of adipose tissue, which can be congenital or acquired. Our results suggest that residual adipose tissue characteristics can help distinguish different subtypes of lipodystrophy.

Figure 1. a–h

Magnetic resonance images of patients with generalized lipodystrophy. Panels (a, b) show control subjects with normal adipose tissue distribution (a, a 28-year-old healthy woman; b, a 26-year-old healthy man). Panels (c, d) show adipose tissue distribution in patients with CGL1: (c), a 30-year-old female (patient 1.1); (d), a 31-year-old male (patient 2.2). Panels (e, f) show adipose tissue distribution in patients with CGL 2: (e), a 25-year-old female (patient 6.1); (f), a 19-year-old male (patient 6.2). Panel (g) shows adipose tissue distribution in a 16-year-old female patient with CGL4 (patient 8.1). Panel (h) shows adipose tissue distribution in an 11-year-old female patient with AGL (patient 10). (I), whole body, coronal T1-weighted imaging; (II), orbital fat and scalp, axial T1-weighted imaging; (III), breasts, axial T1-weighted imaging; (IV), external genital region and palms, axial T1-weighted imaging; (V), soles, axial T1-weighted imaging; (VI), patellar region, axial T1-weighted imaging; (VII), hip region, coronal T1-weighted imaging.

Figure 2. a–h

Magnetic resonance images of patients with partial lipodystrophy. Panels (a, b) show control subjects with normal adipose tissue distribution (a, a 28-year-old healthy woman; b, a 26-year-old healthy man). Panels (c–f) show adipose distribution in FPLD patients: (c), a 30-year-old female with classical codon 482 LMNA mutation (patient 11.1); (d), a 48-year-old female with non-codon 482 LMNA mutation (patient 16.1); (e), a 28-year-old female with PPARG mutation (patient 17.1); (f), a 34-year-old female, mutation negative (patient 18.1). Panels (g, h) show adipose distribution in patients with APL: (g), a 26-year-old male (patient 23); (h), a 32-year-old female (patient 24). (I), whole body, coronal T1-weighted imaging; (II), orbital fat and scalp, axial T1-weighted imaging; (III), breasts, axial T1-weighted imaging; (IV), external genital region and palms, axial T1-weighted imaging; (V), soles, axial T1-weighted imaging; (VI), patellar region, axial T1-weighted imaging.