Can a bone lesion on the iliac crest cause thigh numbness and tingling?

Bone Lesions on the Iliac Crest Can Cause Thigh Numbness and Tingling

Yes, a bone lesion on the iliac crest can cause thigh numbness and tingling, typically by compressing or irritating the lateral femoral cutaneous nerve (LFCN) as it passes near the iliac crest.

Anatomical Basis for Symptoms

The lateral femoral cutaneous nerve (LFCN) is particularly vulnerable to compression or irritation near the iliac crest due to its anatomical course:

• The LFCN typically passes near or under the inguinal ligament, close to the anterior superior iliac spine
• The nerve supplies sensation to the anterolateral aspect of the thigh
• Compression of this nerve results in a condition called meralgia paresthetica, characterized by numbness, tingling, and burning pain in the lateral thigh 1
• There are 9 known anatomical variations of the LFCN in relation to the anterior superior iliac spine and inguinal ligament, making it vulnerable to injury or compression from various pathologies 2

Pathological Mechanisms

A bone lesion on the iliac crest can cause thigh numbness and tingling through several mechanisms:

1. Direct compression: A growing lesion can directly compress the LFCN as it passes near the iliac crest
2. Inflammatory response: Malignant or inflammatory lesions can cause local inflammation that irritates nearby neural structures
3. Infiltration: Malignant lesions may directly infiltrate neural tissue
4. Mass effect: Large lesions can displace surrounding tissues, creating indirect pressure on the nerve

Types of Bone Lesions That Can Cause These Symptoms

Several types of bone lesions affecting the iliac crest have been documented to cause thigh numbness and tingling:

• Malignant deposits: Secondary malignant deposits in the iliac crest can mimic symptoms of meralgia paresthetica 3
• Primary bone tumors: Both benign and malignant primary bone tumors can affect the iliac crest
• Metastatic lesions: As documented in case reports, metastatic lesions to the iliac crest can present with thigh numbness 3
• Soft tissue masses: Even adjacent soft tissue masses like lipomas can compress the LFCN and cause similar symptoms 4

Clinical Significance and Diagnostic Approach

When a patient presents with thigh numbness and tingling with a known iliac crest lesion:

1. Imaging studies are essential: CT scan or MRI of the pelvis can help characterize the lesion and its relationship to neural structures 5
2. Electrophysiological studies: May help confirm LFCN involvement but can sometimes be normal despite symptoms
3. Consider malignancy: Symptoms of meralgia paresthetica can sometimes be the presenting symptom of a malignancy 3
4. Differential diagnosis: Consider other causes of thigh numbness including lumbar radiculopathy, diabetic neuropathy, and direct LFCN compression from other causes

Management Implications

The management approach depends on the nature of the bone lesion:

• Benign lesions: May require surgical excision if causing significant symptoms
• Malignant lesions: Require appropriate oncological management based on the primary cancer
• Symptomatic treatment: May include local anesthetic injections, anti-inflammatory medications, or neuropathic pain medications
• Surgical intervention: In cases where the lesion is amenable to surgical removal, excision may resolve the symptoms 4

Conclusion

Thigh numbness and tingling can indeed be caused by a bone lesion on the iliac crest, primarily through compression or irritation of the lateral femoral cutaneous nerve. This presentation should prompt thorough investigation of the lesion with appropriate imaging studies to determine its nature and guide management decisions. When evaluating patients with thigh paresthesia, clinicians should consider iliac crest pathology in their differential diagnosis, especially when symptoms follow the distribution of the lateral femoral cutaneous nerve.