Diogenes syndrome associated with hyperostosis frontalis interna: A possible role for frontal dysfunction?

Diogenes Syndrome (DS) is defined by the presence of extreme self-neglect, domestic squalor, social withdrawal, excessive hoarding, and lack of concern about living conditions [1]. DS was first reported in elderly patients without mental disease, with high intelligence, and no financial deprivation [2]. Orell proposed that DS could be a manifestation of frontal dysfunction [3]. Successively, Lebert confirmed the frequent presence of some features of DS in patients with fronto-temporal dementia (e.g. self-neglect, decline in personal and environmental hygiene, lack of concern) [4], suggesting that these two conditions might be correlated but distinct. We report a case of DS whose autoptic examination revealed a severe bilateral hyperostosis frontalis interna (HFI). A 78-year-old-woman (P.A.), was admitted to our hospital, coming from the emergency room with the diagnosis of “accidental fall, foul environmental/body hygienic conditions”. Five years before a neighbour signalled to the major of Ferrara the bad hygienic conditions of P.A. and her house. She poked about in dustbins and collected rubbish inside her house; the neighbour had succeeded in getting into her house and cleaning it (removing 140 refuse bags). Therefore P.A. was taken in care by psychiatric service. Her personality was described as shy and closed; her mood was deflected with conceptions of ruin and persecution. She had auditory misperceptions with delusional interpretation, but her MMSE score was normal (26.3/30). From anamnesis, the following data emerged; she was graduated in mathematics, and had worked as a teacher. She had never got married, lived alone, and was currently followed by social workers. At physical examination she looked alert, cooperative, partially oriented in space and time; bulky bilateral cervical lymph nodes enlargements were observed. The SPMSQ score was 7/10 (mild cognitive impairment). P.A. suddenly died after 10 days of hospitalization because of hypovolemic shock. The autopsy report showed a severe bilateral frontal-parietal internal hyperostosis, atherosclerosis involving aorta and Willis's circle, nodal diffuse B-lymphocytic malignant lymphoma with metastases to kidneys, stomach, and bone marrow. The cause of death was a gastric haemorrhage originating from a site of metastasis. HFI is a disorder involving the progressive symmetric thickening of the inner table of the frontal bone, predominantly found in elder women [5]. Stewart and Morel documented an association between HFI and psychiatric disturbances [6], including persecutory delusions and hallucinations. Devriendt found that in a series of 13 HFI cases autopsy observations, 10 had suffered from psychiatric disorders (depressive and/or frontal syndrome), while two were demented [7]. A previous study demonstrated the higher prevalence of HFI among patients from psychiatric compared to general hospital [8], reporting a pathologic pattern of frontal syndrome. Interestingly, de Zubicaray studied one patient with dorsolateral frontal compression due to HFI, and demonstrated a significant impairment in self-ordered working memory tasks concluding that compression secondary to HFI may produce selective cognitive impairment [9]. Finally, neuropsychological studies conducted in patients with HFI causing frontal lobe compression have shown a selective impairment of executive functions, which could be due to frontal bone-cortex conflict [10]. In our case report, a previously unknown severe bilateral frontal-parietal internal hyperostosis emerged in a patient with DS; to our knowledge there are no previous reports associating these two conditions. With an estimated prevalence of 1.6/10.000 for DS [11] and about 10% for HFI [12], the probability of developing both pathologies is 1/62.500. Since frontal lobe compression due to HFI might selectively affect frontal functions [9] and [10], and DS has been consistently associated with frontal dysfunction [3] and [4], we advance that in our case the pathogenesis of DS might be, at least in part, related with the compression of frontal-parietal lobes by severe HFI.