PHALANGEAL MICROGEODIC SYNDROME: IS THIS VERY RARE CONDITION BECOMING MORE COMMON?

ABSTRACT

Background/Aims Phalangeal microgeodic syndrome (PMS) is a rare condition with only a handful of published case reports. Most of these cases are recognised in childhood, typically in Japan. It presents with pain and dusky discolouration in the digits, distinct from Raynaud's phenomenon in that the colour change is fixed and pain constant. Symptom onset is related to cold exposure with first presentation usually occurring in winter. Features on magnetic resonance imaging (MRI) are striking and characteristic, with a distinct pattern of bone marrow oedema. Methods We report five cases of MRI-proven PMS all identified in the last 12 months, with symptom onset during the winter. The patients were all female, aged between 25 and 79. One patient was already under the care of rheumatology with an established diagnosis of systemic lupus erythematosus (SLE), but the remainder were De novo referrals presenting specifically with pain and discolouration of the digits. One patient developed symptoms 2 days after receiving the first dose of Pfizer/ Biontech RNA vaccine against COVID-19. One patient had to self-isolate following a COVID-19 contact and developed symptoms shortly thereafter, although there was no proven infection in the affected individual. Results Four out of five cases were managed conservatively, with advice on maintaining core and peripheral temperature and skin integrity. Without any specific therapy, these four cases improved spontaneously to coincide with increasing seasonal temperatures. The fifth case with existing SLE was treated with intravenous pamidronate and subsequently with a calcium channel blocker, with some improvement in symptoms. Conclusion In these authors' experience, it would seem PMS is increasing in incidence. It is unclear if this relates to wider availability and image quality of MRI, clinician bias due to personal experience of more cases or a genuine increase. The winter 2020/21 was particularly cold with sub-zero conditions lasting well into May, which may have impacted on this flurry of new cases. We have identified one prior case report which describes PMS in a patient with existing connective tissue disease. Our patient with SLE appeared to have a more severe clinical presentation requiring additional medical therapy to control the symptoms compared with the four cases where PMS was a standalone condition. Dermatological manifestations of acute COVID-19 infection are well documented in children and include chilblain-like lesions and acrocyanosis. Any association between COVID-19 and PMS is purely hypothetical and would require more study to identify any true relationship.