Preschooler with left neck mass

US and CT of cervical thymus — Transverse+sagittal US of the neck (above) shows the mass to have a starry sky appearance. Axial+coronal CT with contrast of the neck shows the mass to be inferior to the thyroid and contiguous with the thymus.

The diagnosis was cervical thymus.

Newborn with respiratory distress

CXR of a prominent thymus — CXR AP+lateral shows an anterior mediastinal mass without a thymic wave or thymic sail sign that was confirmed on US to be normal thymic tissue.

The diagnosis was prominent thymus.

Premature newborn with respiratory distress

CXR of normal thymus on rotated CXR — CXR AP rotated to the right shows complete opacification of the right lung apex. Repeat CXR without rotation was unremarkable.

The diagnosis was a rotated CXR accentuating the appearance of a normal thymus.

Newborn with respiratory distress

CXR of normal thymus with wave sign — CXR AP shows an anterior mediastinal mass with a wave-like appearance to the left mediastinal contour.

The diagnosis was normal thymus with a wave sign.

Infant with respiratory distress

CXR of normal thymus with sail sign — CXR AP and lateral shows a prominent anterior mediastinal mass whose right inferior margin appears triangular and sail-like in appearance.

The diagnosis was normal thymus with a sail sign.

Our DDX this week is thymus mass

View the illustrated DDX of thymus mass

Teenager with pleuritic chest pain

Pathological image of Ewing sarcoma of the rib — Pathological image shows a tumor which was brown and grossly necrotic and was seen to be located predominantly in the soft tissues and not in the rib.

The diagnosis was Ewing sarcoma.

Pediatric Imaging Pearl of the Week

View the illustrated DDX of chest wall masses

School ager with a rapidly enlarging soft tissue mass of the right chest and arm

CXR and CT of malignant peripheral nerve sheath tumor in neurofibromatosis type 1 — CXR PA and lateral shows a right apical thoracic mass with associated rib thinning that had rapidly increased in size in a short interval. Axial CT without contrast of the chest better defined the right apical mass and demonstrated multiple serpiginous nodules in the soft tissues of the right anterior chest wall.

The diagnosis was degeneration of a plexiform neurofibroma into a malignant peripheral nerve sheath tumor in a patient with neurofibromatosis type 1.

School ager with cafe-au-lait spots

CXR and CT of plexiform neurofibroma in neurofibromatois type 1 — CXR PA shows a large soft tissue mass in the apex of the right lung which causes thinning of the right 1st-5th ribs posteriorly. CT without contrast of the chest shows multiple small nodules throughout the soft tissues of the chest wall.

The diagnosis was multiple plexiform neurofibromas in a patient with neurofibromatosis type 1.

School ager with an enlarging and tender chest mass who has also had fatigue and weight loss over the last 3 months

CXR and CT of Hodgkins lymphoma with chest wall invasion — CXR PA and lateral shows a large lobulated mediastinal mass compressing and displacing the trachea to the right. Axial CT without contrast of the chest shows the mass to be in the anterior and middle mediastinum, compressing the left mainstem bronchus and eroding into the sternum and chest wall soft tissues.

The diagnosis was Hodgkin Lymphoma.

Newborn with a posterior left chest wall mass on prenatal ultrasound

MRI of lymphatic malformation of the chest wall — Axial T1 without contrast (top), T2 (middle) and T1 with contrast (bottom) MRI of the chest shows a mass composed of multiple large fluid-filled structures separated by thin septations which faintly enhance.

The diagnosis was lymphatic malformation.

Newborn with a large left chest wall deformity

CXR and CT of mesenchymal hamartoma of chest wall — CXR AP shows a large mass arising from the left 4th-6th ribs. Axial CT without contrast of the chest with soft tissue windows (right upper and middle) show the mass to have a fluid-fluid level within it superiorly while bone windows (right lower) show the mass to be calcified.

The diagnosis was mesenchymal hamartoma of the chest wall.

Young adult treated for leukemia as a preschooler, now with new palpable sternal mass

CT of epithelioid sarcoma with pulmonary metastases — Axial CT without contrast of the chest with soft tissue (above) and lung (below) windows shows a heterogeneous mass contiguous with the rectus muscles and anterior to the lower sternum which appears to be eroding into the sternum along with multiple peripheral pulmonary soft tissue nodules.

The diagnosis was epithelioid sarcoma with pulmonary metastases.

Teenager with right posterior chest wall pain and swelling for 2 years

CT of Ewing sarcoma of the rib — Axial CT with contrast of the chest shows a large heterogenous non-enhancing soft tissue mass centered around the posterior aspect of the right 11th rib. 3D CT reconstruction better demonstrates the lesion’s origin from the right 11th rib.

The diagnosis was Ewing sarcoma.

Young adult status post radiation therapy for sarcoma with an incidental finding on CXR

CXR and CT of osteochondroma of the rib — CXR PA shows a calcific density in the head of the left third rib. Contiguous images from an axial CT without contrast of the chest shows a bony outgrowth at the proximal aspect of the left third rib posteriorly.

The diagnosis was osteochondroma of the left third rib.

School ager with cystic fibrosis and a right chest wall mass

CXR of osteomyelitis of the rib — CXR PA and magnified view of the ribs (below) shows dense opacity in the right upper lobe and marked periosteal reaction of the right 4th rib posteriorly.

The diagnosis was botryomycosis (recurrent staphylococcus infection) resulting in osteomyelitis of the rib in a patient with cystic fibrosis.

School ager with a protuberant left chest wall

CXR and CT of pectus excavatum — CXR PA and lateral and axial CT without contrast of the chest shows marked depression of the sternum posteriorly leading to deformation of the chest wall.

The diagnosis was pectus excavatum.

Teen with a palpable anterior left chest wall mass

CXR and CT of rib fusion — CXR shows a contour irregularity of the left second rib anteriorly. 3D CT shows a pseudoarthrosis between the left first and second ribs.

The diagnosis was rib fusion / pseudoarthrosis of the left first and second ribs.

Teenager with left chest wall mass

CXR and CT of rhabdomyosarcoma of the chest wall — CXR PA and lateral (above) shows an ill defined left-sided pleural-based process. Axial CT without contrast of the chest (below) shows a mass arising from the muscles of the left chest wall which invades up into the pleural space and down into the abdomen, sparing the ribs.

The diagnosis was rhabdomyosarcoma.

Newborn with a large soft tissue mass on their back

US and CT of infantile fibrosarcoma — Sagittal US of the mass (above) revealed increased vascularity peripherally and central ulceration. Axial and sagittal CT with contrast of the chest (below) shows a mass arising near the right scapula of heterogenous density with variable enhancement.

The diagnosis was infantile fibrosarcoma.

Infant with torticollis and a right superior chest wall mass

CT and US of fibromatosis coli / torticollis tumor — Axial CT with contrast of the chest (above) shows asymmetry of the sternocleidomastoid muscles, right larger than left. Transverse US of the chest (middle) at the same level of the CT better shows the enlarged right sternocleidomastoid muscle. Sagittal US of the sternocleidomastoid muscles (bottom) shows the normal smooth contour of the left sternocleidomastoid muscle and the spindle shaped appearance of the right sternocleidomastoid muscle.

The diagnosis was fibromatosis colli.

Infant with severe eczema and an enlarging left chest wall mass over the last week and elevated white count

CT and MRI of osteomyelitis of the rib — Axial CT without contrast of the chest (above) shows bilateral axillary adenopathy and soft tissue swelling over the left lateral chest wall and associated rib destruction. Coronal T2 MRI of the chest (below left) shows a high signal intensity fluid collection between the skin and the ribs with surrounding edema. Axial T1 MRI with contrast of the chest (below right) shows extensive enhancement of the left ribs and surrounding muscle.

The diagnosis was cellulitis and a subcutaneous abscess resulting in osteomyelitis of the rib via direct extension. The abscess was drained operatively and grew staphlococcus.

Preschooler with a subxiphoid chest wall mass

CT of lipoma of the chest wall and thigh — Axial CT without contrast shows a symmetrical appearing chest wall (top), a fat density center-right sided chest wall mass (middle) and a fat density anterior left thigh mass (bottom).

The diagnosis was lipoma of the chest wall and left thigh.

Our DDX For This Week Is

View the illustrated DDX of chest wall masses