3.2.1 Diagnostic Considerations
This case highlights the importance of an accurate diagnosis and the
need for improved familiarity and understanding of vascular anomalies by
providers as well as by families and patients. In our patient’s case,
the excised “cyst” was a LM, which was confirmed upon review of his
prior pathology. While an isolated LM would not raise suspicion for a
CLA, this history was an important clue in his final diagnosis. The
combination of soft tissue LM, lytic lesions of the ribs and development
of a large chylothorax raises suspicion for CLA. Given concern for GLA,
MRI of the abdomen, pelvis and spine revealed lesions in the pelvic
bone, multiple vertebrae, and spleen as well as the presence of multiple
mesenteric and retroperitoneal cysts (Figure 2B) . No cortical
bone destruction was evident on imaging. Chest imaging with CT or MRI is
also indicated in the workup of possible GLA, which our patient had
after chest tube placement. Echocardiogram did not demonstrate
pericardial effusion. Given the constellation of these findings, he was
diagnosed with GLA.
Bone lesions are a common finding in pediatric and adult patients. Most
bone lesions are benign tumors in children. Plain film is the primary
modality in the initial evaluation of osseous abnormalities, although
diagnosis is not always straight-forward and may require CT or MRI. In
many instances, a characteristic radiologic appearance on plain film,
along with age of patient, location of the lesion(s) and presenting
symptoms, helps differentiate benign from malignant lesions. Benign
lesions, including those in CLA, typically demonstrate bone destruction
with well-demarcated margins. However, multiple myeloma and metastases
must be evaluated for in adults, particularly when older than 40 years
of age. In children, the differential diagnoses for multiple sharply
defined osteolytic lesions is narrower and includes LCH and multiple
enchondromas. Other benign lesions that are generally singular in
nature, such as non-ossifying fibroma, chondroblastoma, chondromyxoid
fibroma, osteoid osteoma, giant cell tumor, unicameral and aneurysmal
bone cysts, also appear radiolucent on plain film but can typically be
differentiated from CLA on MRI or CT imaging, if not by plain film. In
children with CLA, bone lesions are frequently found incidentally or
with pathologic fractures. When bone pain, laboratory abnormalities, or
systemic signs and symptoms are present, metastatic neuroblastoma,
Ewing’s sarcoma, acute leukemia and osteomyelitis must also be
considered. Chronic pain is a frequent presentation in adolescents and
adults with CLA.