Presentation
Left thigh bone pain. HIV negative. Normal renal, hematological and liver function.
Patient Data
Aggressive periosteal reaction involving the upper two thirds of the left femoral shaft. Proximal and distal ends of the reaction are lamellated. Codman's triangle component present in the more superficial areas of the reaction. Associated soft tissue mass. Calcifications within the mass.
Mild patchy sclerosis of the underlying medullary cavity near the center of the periosteal reaction. No abnormalities in the femoral heads or necks. No right sided cortical or medullary abnormalities. The knees are unremarkable.
Left diaphyseal femur lesion demonstrating T1 low signal with associated periosteal reaction and cortical errosion.
Accompanying large soft tissue mass involving the anterior, medial and posterior compartment of the thigh, with associated surrounding edema of the musculature.
The soft tissue mass demonstrate T2 signal hyperintensity with impression of Hair on end low signal striations best seen on the sagital sequence, intermediate signal noted on T1 and heterogeneous post contrast enhancement.
Mid-diaphyseal intramedullary STIR and post contrast enhancement of the femur up to the level of the proximal femur metaphysis.
The soft tissue mass measures approximately 77.4 x 59.7 mm (axial) by 122 mm (cc).
Unremarkable hip and knee joints.
HISTOLOGY REPORT
Type of specimen
Left leg disarticulation
Gross examination
The specimen consists of a left leg disarticulation that weighs 3600 g and measures 655 x 155 x 102 mm. On cut section, a tumor involving the diaphysis of the proximal femur is identified. The tumor measures 130 x 60 x 56 mm. 60% Of the tumor is necrotic. The tumor invades the soft tissue. No skip lesions are identified and no joint space involvement is present. A scar is present overlying the tumor. The closest surgical margin is the lateral soft tissue margin that measures 23 mm.
Key to blocks
A1 & A9: Bone margin (greater trochanter)
A2 : Lesser trochanter
A3 : Soft tissue surrounding the lesser trochanter A4-5 : Representative sections of the tumor
A6 : Tumor and associated bone
A7 : Scar
A8 : Bone marrow
Microscopic examination
Microscopic examination of the bone margin (greater trochanter) shows no tumor present. Microscopic examination of the lesser trochanter also shows no tumor present. Despite the evaluation of numerous deep sections of the soft tissue surrounding the lesser trochanter, no tumor can be identified. Microscopic examination of the bone marrow shows normal, hypocellular bone marrow.
Microscopic examination of the tumor shows treatment effect with numerous fibrous areas. Invasion into the surrounding soft tissue is identified and no lymphovascular invasions is present. Osteoid as well as abundant cartilaginous tissue is identified. Microscopic examination of the surgical scar shows a foreign body giant cell reaction to suture material. No surgical seeding of the tumor is present.
Morphological features are consistent with a periosteal osteosarcoma that has been completely excised.
Pathologic Stage Classification (AJCC 8th Edition) yT2 yNx yMx
Diagnosis
Left leg disarticulation: Periosteal osteosarcoma / yT2 yNx yMx /
Completely excised / With tumor response
Case Discussion
Imaging features suggestive of and histology confirming periosteal osteosarcoma.