Tumoral calcium pyrophosphate dihydrate crystal deposition disease: a rare diagnosis by fine-needle aspiration

Lumbar Extradural Pseudogout Mass Manifesting as Radiculopathy: A Case Report

BACKGROUND

Calcium pyrophosphate dihydrate (CPPD) disease, also known as pyrophosphate arthropathy or pseudogout, is defined as CPPD deposition within the articular cartilage. It was first described in 1962. The representative locations where CPPD disease occurs include the most common knee joint, followed by the wrist joint. Joint swelling and pain are the most common clinical presentations, and the typical differential diagnosis is degenerative arthritis. Microscopically, the specimen demonstrates numerous positively birefringent rhomboid shaped crystals when examined under polarized light.

CASE REPORT

We present a 70-year-old female with right painful sciatica accompanied by coexisting affected limb soreness and clumsiness. Her final diagnosis was unusual lumbar extradural tumoral pseudogout that was worth noticing. Tumoral CPPD deposition was excised after laminectomy. Subsequently, her symptoms were abated postoperatively without a need for more analgesics. Her neurological function was properly recovered.

CONCLUSION

This is a rare report to proffer pseudogout in an unfamiliar lumbar extradural location, which is an unexpected diagnosis. Making a precise tentative diagnosis for the ongoing disease entity might be difficult for the clinicians because the clinical manifestations of this pathology are similar to those of other common degenerative lumbar spinal diseases.

Calcium pyrophosphate dihydrate deposition disease of the filum terminale

INTRODUCTION

Calcium pyrophosphate dihydrate crystal deposition disease (CPPDD) is a rare benign inflammatory joint disorder characterized by the presence of calcium pyrophosphate dihydrate crystal in the interarticular and periarticular tissue. It has been rarely described with spinal localization.

METHODS

A 50-year-old woman, affected by CPPDD, presented a progressive weakness of both lower limbs associated with neurogenic claudication. Neuroradiological examinations revealed the presence of two intradural calcified lesions at level L3-L4, with no post-contrast enhancement.

RESULTS

Surgery was performed and the histopathological exams documented the presence of rod-shaped crystals embedded in a fibrocartilaginous stroma. The postoperative course was uneventful and the patient experienced complete symptoms relief with a 5-year follow-up.

CONCLUSION

Intradural CPPD localization at the filum terminale is an extremely rare occurrence. Total removal should be preferably attempted with a long-term focal control of the disease as we observed in our case.