Age / Sex : 38 / F

Chief complaint : left inguinal pain


What is your diagnosis?

Two weeks later, you can see the final diagonosis with a brief discussion of this case (Please submit only one answer).


Courtesy : 박희진, Hee Jin Park, 강북삼성병원, Kangbuk Samsung hospital

Nodular fasciitis

Discussion

Findings:

USG – Hard, Partially ill-defined low echogenic mass

MRI-- Hyper SI to that in adipose tissue on T2WI, Subtle hyper SI to that in skeletal muscle on PDWI

Differential Diagnosis:

metastatic lymph node

Schwannoma arising from femoral nerve

Diagnosis: 

Nodular fasciitis

Discussion:

Benign soft tissue lesion composed of proliferating fibroblasts

WHO classification of soft tissue tumors

Under "fibroblastic/myofibroblastic tumors

Peak age : 2nd~4th decades, no sex predominance

Upper extremity, particularly the volar aspect of the forearm (~45%) > trunk (20%)> head and neck(18%) > lower extremity(16%)

3 general subtypes on the basis of the lesion location, Relationship to deep fascia

Subcutaneous

Fascial

Intramuscular

Poorly understood pathogenesis

Reactive lesion related to trauma

Chromosomal abnormalities that are suggestive of a neoplastic origin

Radiographic features

 Small (<4 cm)

 Well circumscribed but lack true encapsulation components

Ultrasound

In the deep portion of the subcutaneous fat layer, adjacent to or in the fascia

Well-defined isoechoic to hypoechoic nodules

with a mildly increased vascular flow

References:

1. Differential of a Soft Tissue Mass of the Tendon Sheath, ESSR  2015 / P-0098


2. Tumors and tumor-like lesions of infrapatellar fat pad and surrounding tissues: A review of the literature, Eklem Hastalik Cerrahisi 2018;29(1):58-62