Scalp skin biopsy helps diagnose spinal sarcoidosis: Case report
Biopsy sites other than spine worth considering, doctors say
A 79-year-old woman was diagnosed with spinal sarcoidosis based on the analysis of skin lesions from her scalp, according to a case study from Japan.
Although a spinal MRI revealed the presence of spinal cord lesions, their cause was unknown. The presence of skin granulomas, observed in a scalp skin biopsy, was indicative of sarcoidosis.
That means “we should carefully observe skin lesions, especially on the scalp,” the researchers wrote in the case report, “Usefulness of a Scalp Biopsy for Diagnosing Spinal Sarcoidosis,” published in Internal Medicine.
Sarcoidosis is characterized by the formation of clumps of abnormally activated immune cells, called granulomas, in tissues and organs including the skin, lungs, heart, and nervous system.
Roughly 5% to 15% of sarcoidosis patients develop granulomas in either the central nervous system (CNS) — the brain and spinal cord — or along peripheral nerves located outside the CNS. However, these granulomas are often difficult to diagnose.
Gait problems had surfaced two years earlier
Researchers at Kanazawa University in Japan described the case of the woman, who had developed gait problems about two years before. A neurological examination revealed she had weakness in the limbs, as well as sensory issues in the trunk and extremities.
She also displayed an abnormal reflex, known as the plantar reflex, in both feet, which could be indicative of a spinal cord disorder. She had no visible skin lesions on the face, limbs, or trunk.
An MRI of the spine revealed the presence of lesions in the cervical region, or the neck area, of the spinal cord. Positron emission tomography (PET), a technique that uses a small amount of radioactive material to create detailed images of internal structures, showed a skin lesion in the scalp, with skin pigmentation observed in the same location.
A biopsy of the lesion, in which a small sample of tissue is removed and examined in the lab, revealed the presence of cell granuloma in the epithelial cells, the most abundant cells covering the skin. The granuloma was identified as non-caseating, indicating that it did not exhibit any cell death. This type of granuloma is frequently associated with inflammatory disorders.
Based on these results, and considering the patient had normal blood levels of tumor markers, anti-aquaporin-4 antibodies, angiotensin-converting enzyme (a protein that regulates blood pressure) and vitamin B12, doctors diagnosed the patient with spinal sarcoidosis.
Anti-aquaporin-4 antibodies are commonly found in patients with neuromyelitis optica spectrum disorder (NMOSD), an autoimmune disease that leads to the progressive inflammation of the spinal cord, leading to limb weakness and loss of sensation.
Vitamin B12 is also associated with subacute combined degeneration, a disorder of the spine that also causes weakness and abnormal sensations.
Considering spinal biopsies are challenging, the researchers concluded that “biopsy sites other than spinal lesions may aid in the diagnosis of spinal sarcoidosis.”
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