A 61-year-old female patient presented for a 3-months period with hypoaesthesia of both lower limbs and gait disturbance without motor symptoms.
On past medical history the patient referred a previous B12-deficiency and a chronic atrophic gastritis.
Neurological examination objectified tactile hypoaesthesia of both lower limbs and normal pain perception and proprioception.
No pathological findings were observed on LCR and blood samples.
Spinal cord MRI was performed revealing multiple and confluent lesions affecting both posterior and lateral columns of the entire spinal cord. Lesions were hyperintense on T2-weighted sequences, without enhancement after gadolinium injection. On the axial plane posterior columns lesions showed inverted “V”-morphology. Anterior columns were not affected. Brain MRI did not show pathological findings.
MRI findings, along with present and past medical history, suggested a subacute combined spinal cord degeneration, caused by the previous vitamin B12-deficiency.
Subacute combined spinal cord degeneration is an acquired progressive myelopathy caused by B12-deficiency, a vitamin necessary for normal turn-over of myelin sheath that surrounds nerve fibers. Its deficiency can be caused by inadequate dietary intake or, more frequently, by inadequate gastrointestinal absorption for autoimmune gastritis or previous surgery. Clinical presentation of subacute combined spinal cord degeneration consists mainly of sensory symptoms as paraesthesia, sensory loss and gait ataxia. If left untreated, the disease may progress to ataxic paraplegia.
Normally, B12-deficiency goes along with megaloblastic anaemia, although lack of parallelism between haematologic and neurologic findings is well-known and frequently reported in literature [1–3]: this was the case for our patient.
MRI findings consist of demyelinating lesions affecting posterior and, more rarely, lateral columns of the spinal cord. Lesions are typically T2-hyperintense showing the characteristic “V” inverted sign; contrast-enhancement is rare and when present very mild . Long lasting lesions may result in spinal cord atrophy.
Demyelinating lesions in cerebral deep white matter are uncommon but reported in literature .
Diagnosis is made by MRI and low serum B12-level or elevated levels of the metabolites homocysteine and methylmalonic acid .
Differential diagnosis is broad and includes copper deficiency and inflammatory and demyelinating disorders such as multiple sclerosis, neuromyelitis optica and neurosarcoidosis.
Treatment of B12-deficiency by monthly B12 intramuscular injections.
At an older age, presence of extensive lesions and longer duration of illness are negatively related to resolution of lesions and clinical signs. This relationship underscores the importance of early diagnosis.
Diagnosis of subacute combined spinal cord degeneration must be suspected in the presence of characteristic radiologic and clinical findings even in the absence of macrocytic anaemia.
The aforementioned patient received weekly B12 intramuscular injection with clinical improvement and was therefore discharged.
Written informed patient consent for publication has been obtained.
 Victor M, Lear AA (1956) Subacute combined degeneration of the spinal cord; current concepts of the disease process; value of serum vitamin B12; determinations in clarifying some of the common clinical problems. Am J Med 20(6):896-911 (PMID: 13326904)
 Vasconcelos OM, Poehm EH, McCarter RJ, Campbell WW, Quezado ZM (2006) Potential outcome factors in subacute combined degeneration: review of observational studies. J Gen Intern Med 21(10):1063-8 (PMID: 16970556)
 Healton EB, Savage DG, Brust JC, Garrett TJ, Lindenbaum J (1991) Neurologic aspects of cobalamin deficiency. Medicine (Baltimore) 70(4):229-45 (PMID: 1648656)
 Larner AJ, Zeman AZ, Allen CM, Antoun NM (1997) MRI appearances in subacute combined degeneration of the spinal cord due to vitamin B12 deficiency. J Neurol Neurosurg Psychiatry 62(1):99-100 (PMID: 9010410)
 Briani C, Dalla Torre C, Citton V, Manara R, Pompanin S, Binotto G, Adami F (2013) Cobalamin deficiency: clinical picture and radiological findings. Nutrients 15;5(11):4521-39 (PMID: 24248213)
 Wolffenbuttel BHR, Wouters HJCM, Heiner-Fokkema MR, van der Klauw MM (2019) The Many Faces of Cobalamin (Vitamin B12) Deficiency. Mayo Clin Proc Innov Qual Outcomes 3(2):200-214 (PMID: 31193945)