A spiculated nodule is a lung nodule with irregular, radiating margins or projections extending into the surrounding lung parenchyma.
This finding is commonly associated with malignant lesions due to tumor infiltration into adjacent tissue but can occasionally be seen in benign conditions.
Etymology:
Derived from the Latin word spiculum, meaning “a sharp point or spike,” describing the radiating projections around the nodule.
AKA:
Stellate nodule.
Abbreviation:
SN (Spiculated Nodule).
How does it appear on each relevant imaging modality:
Chest CT (preferred):
Parts: A central solid or subsolid nodule with spiculations radiating outward.
Size: Can range from small (<1 cm) to larger lesions (up to 3 cm, classified as a mass if larger).
Shape: Irregular or lobulated with characteristic spiculated margins.
Position: Commonly located in the upper lobes but can occur in any lobe.
Character:
Soft tissue density with irregular or spiked margins.
May show heterogeneity, cavitation, or contrast enhancement in malignant cases.
Chest X-ray:
Appears as a nodular opacity with indistinct or radiating edges.
Spiculation may be subtle and better visualized on CT.
PET-CT:
Increased SUV uptake (>2.5) in spiculated nodules suspicious for malignancy but can be inflammatory or infectious
SUV uptake (3-4 )highly suspicious .
Differential diagnosis:
Infection:
Post-inflammatory scarring from prior infections (e.g., tuberculosis, fungal infections).
Inflammation:
Rheumatoid nodules or
sarcoidosis with spiculated features due to adjacent fibrosis.
Neoplasm:
Malignant: Primary lung cancer (e.g., adenocarcinoma, squamous cell carcinoma).
Metastatic lesions with irregular margins.
Idiopathic:
Cryptogenic organizing pneumonia (COP) with fibrotic features mimicking spiculation.
Recommendations:
Further evaluation:
Contrast-enhanced CT for detailed evaluation of margins, vascularity, and internal composition.
PET-CT for metabolic activity and staging if malignancy is suspected.
Biopsy (CT-guided or bronchoscopic) for histopathological diagnosis in suspicious cases.
Surveillance:
Follow-up CT imaging per Fleischner Society guidelines for indeterminate nodules.
Key considerations and pearls:
Spiculated nodules are highly suspicious for malignancy, particularly in older patients, smokers, or those with systemic symptoms.
Benign causes of spiculation are less common and often related to post-inflammatory fibrosis.
Rapid growth (doubling time <30-400 days), increased metabolic activity on PET-CT, and upper lobe location further raise suspicion for malignancy.
Always correlate imaging findings with clinical history to guide appropriate management.
