Klippel-Trenaunay syndrome or not? An exploration of atypical presentations.

Klippel-Trenaunay syndrome (KTS) is a rare, congenital disorder typically emerging in early infancy or childhood. The classic presentation of KTS is distinguished by a triad of clinical features: a port-wine stain, early-onset varicosities and limb overgrowth. However, a notable variant of KTS has been documented, characterised by limb shortening rather than lengthening, occasionally referred to as 'inverse KTS'. This report details two cases that display this unusual presentation-both patients had classical features of port-wine stain and varicose veins but both experienced shortening of the affected limb. Whether these cases represent a variant of KTS or a new clinical syndrome altogether is uncertain. They however offer valuable insights into the nuances and breadth of clinical manifestations associated with this syndrome.

The Etiology and Outcome of Area Postrema Syndrome in Childhood: Two Cases and a Literature Review.

BACKGROUND: Area postrema syndrome (APS), a rare childhood condition, manifests as intractable nausea and hiccups. APS has high diagnostic significance in neuromyelitis optica syndrome spectrum disorders (NMOSD) and can be the initial presentation of other critical diseases, including brainstem glioma. METHODS: We described two representative cases of unrelated Japanese patients with APS. An etiologic evaluation, including a detailed intracranial neuroradiological examination and autoantibodies assessment, was performed. We also reviewed the literature focusing on the prognosis of pediatric APS symptoms. RESULTS: A 14-year-old girl with aquaporin-4 antibody-positive NMOSD showed a good prognosis with immunotherapy, whereas another nine-year-old girl with irresectable medullary low-grade glioma had persistent symptoms for more than 10 years. All reported children aged >12 years were diagnosed with NMOSD, and patients aged <13 years showed heterogeneous etiologies. CONCLUSIONS: Distinctive time courses and neuroimaging features were key clinical findings for the diagnostic and therapeutic processes in these patients. This literature review highlights the wide spectrum and prognosis of pediatric-onset APS.

Diagnosis of cystic lung diseases: a position statement from the UK Cystic Lung Disease Rare Disease Collaborative Network.

BACKGROUND: Rare cystic lung diseases are increasingly recognised due the wider application of CT scanning making cystic lung disease management a growing part of respiratory care. Cystic lung diseases tend to have extrapulmonary features that can both be diagnostic but also require surveillance and treatment in their own right. As some of these diseases now have specific treatments, making a precise diagnosis is crucial. While Langerhans cell histiocytosis, Birt-Hogg-Dubé syndrome, lymphoid interstitial pneumonia and lymphangioleiomyomatosis are becoming relatively well-known diseases to respiratory physicians, a targeted and thorough workup improves diagnostic accuracy and may suggest other ultrarare diseases such as light chain deposition disease, cystic pulmonary amyloidosis, low-grade metastatic neoplasms or infections. In many cases, diagnostic information is overlooked leaving uncertainty over the disease course and treatments. AIMS: This position statement from the Rare Disease Collaborative Network for cystic lung diseases will review how clinical, radiological and physiological features can be used to differentiate between these diseases. NARRATIVE: We highlight that in many cases a multidisciplinary diagnosis can be made without the need for lung biopsy and discuss where tissue sampling is necessary when non-invasive methods leave diagnostic doubt. We suggest an initial workup focusing on points in the history which identify key disease features, underlying systemic and familial diseases and a clinical examination to search for connective tissue disease and features of genetic causes of lung cysts. All patients should have a CT of the thorax and abdomen to characterise the pattern and burden of lung cysts and extrapulmonary features and also spirometry, gas transfer and a 6 min walk test. Discussion with a rare cystic lung disease centre is suggested before a surgical biopsy is undertaken. CONCLUSIONS: We suggest that this focused workup should be performed in all people with multiple lung cysts and would streamline referral pathways, help guide early treatment, management decisions, improve patient experience and reduce overall care costs. It could also potentially catalyse a national research database to describe these less well-understood and unidentified diseases, categorise disease phenotypes and outcomes, potentially leading to better prognostic data and generating a stronger platform to understand specific disease biology.

[Neuropathic pain as a symptom in autonomic neuropathies and other rare diseases : Small fiber neuropathy: its recognition, diagnosis, and treatment]. / Neuropathische Schmerzen als Symptom bei autonomen Neuropathien und anderen seltenen Erkrankungen : Kleinfaserneuropathie erkennen, diagnostizieren und behandeln.

BACKGROUND: Neuropathic pain is difficult to diagnose and treat. Small fiber neuropathy (SFN) flies under the radar of nerve conduction studies. OBJECTIVES: The importance of a structured patient history and physical examination in the context of neuropathic pain is emphasized. Describing SFN as an important cause, the authors consider rare but partially treatable differential diagnoses. They conclude that autonomic symptoms are frequently associated, often presenting with diverse symptoms. METHODS: A selective literature research to present SFN symptoms as well as differential diagnostic and therapeutic steps in the context of SFN and rare diseases focusing on the autonomic nervous system. RESULTS: Neuropathic pain significantly reduces quality of life. To shorten the time until diagnosis and to initiate therapy, the authors recommend a structured patient history including sensory plus and minus symptoms and non-specific autonomic signs. If the initial search for the cause is not successful, rare causes such as treatable transthyretin (ATTR) amyloidosis and Fabry's disease or autoimmune causes should be considered, particularly in the case of progressive and/or autonomic symptoms. CONCLUSION: The diagnosis and therapy of rare SFN requires interdisciplinary collaboration and, in many cases, a referral to specialized centers to achieve the best patient care.

Tracheobronchopathia Osteochondroplastica - to Biopsy or not to Biopsy? A Relook at The Rare Disease.

BACKGROUND: Tracheobronchopathia osteochondroplastica (TPO) is a rare idiopathic disease involving the tracheobronchial tree. It is mostly an incidental finding with non-specific clinical manifestations. It has typical bronchoscopic, radiological features and biopsy is usually considered non-essential. The study aimed to determine whether biopsy makes a difference in the management of patients. METHODS: All patients diagnosed with TPO in our institution over 15 years (2005 to 2020) were included in this study. Their medical records, chest computed tomography (CT), and bronchoscopy reports were retrospectively reviewed, and data were analysed. All the CT images were reviewed by a senior chest radiologist. RESULTS: From the 20,000 bronchoscopies and 260,000 CT thorax images obtained, 28 cases were diagnosed as TPO based on either bronchoscopy or radiology or both. Among the 19 cases diagnosed through bronchoscopy, 16 underwent a biopsy. In addition to TPO features, biopsy showed additional diagnoses in 6 cases. In 9 cases, TPO was not initially diagnosed by CT but by bronchoscopy. In 8 patients, TPO was diagnosed incidentally on CT performed for other reasons. On follow-up with the treatment of underlying/co-existing concomitant aetiologies, clinical improvement was noted in all patients. None of them progressed to respiratory failure or airway obstruction until the last follow-up. CONCLUSION: Among patients who underwent bronchoscopic biopsy of TPO lesions, 38% had biopsy results showing an alternative aetiology, which led to changes in the treatment plan for all these patients. Hence, a bronchoscopic biopsy of TPO lesions should be performed to rule out other aetiologies.

Metabolic crisis in maple syrup urine disease: an unusual complication of a rare disease: a case report.

A 19-year-old woman with known maple syrup urine disease presented to hospital with metabolic crisis in the setting of influenza type A infection and intractable vomiting, rapidly progressing to acute cerebral oedema manifesting as refractory seizures and decreased level of consciousness needing emergency intubation and mechanical ventilation, continuous veno-venous haemodiafiltration and thiopentone coma. A computed tomography scan and magnetic resonance imaging of the brain demonstrated classic signs of cerebral oedema secondary to a metabolic crisis from the metabolic disorder. Her management posed multiple challenges to all teams involved due to lack of familiarity and experience in managing this clinical scenario in the adult intensive care setting.

[Brain abscess as a complication of pulmonary manifestation of HHT]. / Hirnabszess als Komplikation bei pulmonaler Manifestation einer HHT.

A 43-year-old female patient with a brain abscess and a complicated clinical course was diagnosed with hereditary haemorrhagic telangiectasia (HHT) at the Martin Zeitz Centre for Rare Diseases in Hamburg, Germany. The brain abscess was caused by pulmonary arteriovenous malformations (AVM), a typical finding in HHT. Patients with cryptogenic brain abscess should be screened for pulmonary AVM and HHT. This case report illustrates the importance of patient history and interdisciplinary exchange in patients with a broad clinical spectrum as well as interdisciplinary treatment in the case of complications of rare diseases.

Neurological manifestation of HEV infection: still a rare disease entity?

Hepatitis E virus (HEV) infection is the most common form of viral hepatitis and is reported to cause neurological manifestation in up to 30% of diagnosed infections. We evaluated the medical reports of all patients (n = 29,994) who were discharged from the Department of Neurology of Ulm University between 01.01.2015 and 30.09.2022 to detect neurological manifestations of HEV. In addition, we retrospectively analyzed the serum samples of n = 99 patients representing different neurological diseases possibly related to HEV for anti-HEV-IgM and anti-HEV-IgG. At the time of discharge from hospital, the etiology of neurological symptoms in these patients was unclear. Overall, five cases of extrahepatic neurological manifestation of HEV (defined as anti-HEV-IgM and HEV-IgG positive) could be detected. An increase of both, anti-IgM- and anti-IgG-serum levels was significantly more common in neuralgic amyotrophy/plexus neuritis/radiculitis than in AIDP/CIDP (P = 0.01), meningitis/encephalitis (P = 0.02), idiopathic peripheral facial paralysis (P = 0.02) and tension headache (P = 0.02). In 15% (n = 15 out of 99) of retrospectively analyzed serum samples, conspicuous positive anti-HEV-IgG levels were detected. This finding was most common in AIDP/CIDP. In conclusion, results of this study indicate neurological manifestation of HEV to be a rare but still underestimated course of disease, occurring at any age and gender. Therefore, testing for HEV should be considered in patients with neurological symptoms of unknown origin, especially in those with neuralgic amyotrophy/plexus neuritis.

Liver Dysfunction in Adult Hemophagocytic Lymphohistiocytosis: A Narrative Review.

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening condition that has been increasingly recognized in adults and is characterized by a hyperinflammatory state due to immune dysregulation. Its nonspecific presentation, the lack of clinician familiarity given its rarity, and shared clinical features with sepsis and other syndromes can lead to a delay in diagnosis and a poor prognosis. Significant liver function abnormalities as the initial manifestation of HLH are uncommon and can range from mild elevation of aminotransferases to fulminant hepatic failure with high mortality rates. The authors encountered a case of adult HLH mimicking acute viral hepatitis in which a markedly elevated ferritin level led to a prompt diagnosis, early initiation of treatment, and a successful outcome. Clinicians, including gastroenterologists and hepatologists, are often called upon to evaluate patients with abnormal liver tests and may lack experience in the early diagnosis and management of liver dysfunction in the context of HLH. Thus, we expand our reporting to a narrative review of literature which explores the pathogenesis of HLH, challenges associated with its diagnosis, previous reports of liver disease associated with the syndrome, recommended treatments for the familial and adult variations including the role of liver transplantation, and the outcomes of these treatments.

Flemish network on rare connective tissue diseases (CTD): patient pathways in systemic sclerosis. First steps taken.

Despite the low prevalence of each rare disease, the total burden is high. Patients with rare diseases encounter numerous barriers, including delayed diagnosis and limited access to high-quality treatments. In order to tackle these challenges, the European Commission launched the European Reference Networks (ERNs), cross-border networks of healthcare providers and patients representatives. In parallel, the aims and structure of these ERNs were translated at the federal and regional levels, resulting in the creation of the Flemish Network of Rare Diseases. In line with the mission of the ERNs and to ensure equal access to care, we describe as first patient pathways for systemic sclerosis (SSc), as a pilot model for other rare connective and musculoskeletal diseases. Consensus was reached on following key messages: 1. Patients with SSc should have multidisciplinary clinical and investigational evaluations in a tertiary reference expert centre at baseline, and subsequently every three to 5 years. Intermediately, a yearly clinical evaluation should be provided in the reference centre, whilst SSc technical evaluations are permissionably executed in a centre that follows SSc-specific clinical practice guidelines. In between, monitoring can take place in secondary care units, under the condition that qualitative examinations and care including interactive multidisciplinary consultations can be provided. 2. Patients with early diffuse cutaneous SSc, (progressive) interstitial lung disease and/or pulmonary arterial hypertension should undergo regular evaluations in specialised tertiary care reference institutions. 3. Monitoring of patients with progressive interstitial lung disease and/or pulmonary (arterial) hypertension will be done in agreement with experts of ERN LUNG.

Continuous Unilateral Cephalalgia Due to Systemic Lupus Erythematosus: A Case Report / Cefaleia unilateral contínua por lúpus eritematoso sistêmico: relato de caso

BACKGROUND: Hemicrania continua is a rare form of cephalalgia featuring a chronic and persistent headache in only one side of the head. OBJECTIVES: In this report, we present a case of a patient with hemicrania continua and systemic lupus erythematosus (SLE). METHODS: We collected patient data through the electronic medical record. Afterward, we reviewed the literature regarding hemicrania continua and its pathophysiology and correlation with neurovascular alterations, inflammation, and SLE. RESULTS: A 42-year-old woman visited the emergency department due to worsening constant unilateral cephalalgia that had been present for the past 6 months. The patient reported a highly intense (10/10) headache in the entire left hemicrania that radiated to the left shoulder. During physical examination, she presented with nystagmus, vertigo, and aggravated cephalalgia associated to body movement and, despite having no optic nerve thickening. In addition, she had jaundice, tachycardia, and splenomegaly. Complimentary exams found deep anemia, depletion in complement system and anti-nuclear factors, suggesting a possible hemolytic anemia (AIHA) due to SLE. Treatment was initiated with hydrocortisone and prednisone, associated with amitriptyline, fluoxetine and diazepam, reaching full remission. CONCLUSION: These syndromes have aggravated each other, and possibly the explanation for the cephalalgia remission was the control of AIHA and SLE. It features a rare case in literature and thus warrants discussion.

INTRODUÇÃO: Hemicrania contínua é uma forma rara de cefaléia caracterizada por cefaleia crônica e persistente em apenas um lado da cabeça. OBJETIVOS: Neste relato apresentamos o caso de um paciente com hemicrania contínua e lúpus eritematoso sistêmico (LES). MÉTODOS: Coletamos dados dos pacientes por meio do prontuário eletrônico. Posteriormente, revisamos a literatura sobre a hemicrania contínua e sua fisiopatologia e correlação com alterações neurovasculares, inflamação e LES. RESULTADOS: Uma mulher de 42 anos recorreu ao serviço de urgência devido ao agravamento da cefaleia unilateral constante, presente nos últimos 6 meses. O paciente relatou cefaleia de alta intensidade (10/10) em toda a hemicrânia esquerda com irradiação para o ombro esquerdo. Ao exame físico apresentava nistagmo, vertigem e cefaléia agravada associada à movimentação corporal e, apesar de não apresentar espessamento do nervo óptico. Além disso, ela apresentava icterícia, taquicardia e esplenomegalia. Os exames complementares evidenciaram anemia profunda, depleção do sistema complemento e fatores antinucleares, sugerindo uma possível anemia hemolítica (AIHA) por LES. Iniciou-se tratamento com hidrocortisona e prednisona, associadas a amitriptilina, fluoxetina e diazepam, atingindo remissão completa. CONCLUSÃO: Essas síndromes agravaram-se mutuamente e possivelmente a explicação para a remissão da cefaléia foi o controle da AIHA e do LES. Apresenta um caso raro na literatura e, portanto, merece discussão.

A rare disease in adult women: Gaucher disease.

Gaucher disease is a rare, autosomal recessive disorder caused by inborn errors of metabolism. Globally, more than 27 million people are born each year, and approximately 19,000 neonates are born with lysosomal storage disease. We report a rare case of Gaucher disease in an adult female patient of non-consanguineous parents in a subtropical area of Jiangxi Province, China. This area has a high prevalence of schistosomiasis. The diagnosis of this case posed a great challenge because of the possible differential diagnoses of pancytopenia with hepatomegaly and giant splenomegaly. The key component of the patient's diagnosis was her medical history in which it was documented that her brother had died of hepatocellular carcinoma of unknown origin. We diagnosed the patient through a combination of a pathological biopsy and imaging plus the patient's medical history.

[Multisystem lesions in orphan diseases: rheumatological aspects of Fabry's disease. Case report].

Fabry-Andersen disease is a genetically determined, progressive disease related to lysosomal storage diseases, linked to the X chromosome, characterized by impaired glycosphingolipid metabolism, due to the deficiency or absence of the enzyme α-galactosidase A. Fabry disease is a multisystem disease and is characterized by damage to vital organs - kidneys, heart, brain, with the occurrence of complications that cause an unfavorable prognosis. Autoinflammation mechanisms with signs of chronic inflammation are involved in the pathogenesis of the disease. One of the features of Fabry disease are clinical manifestations in the form of arthralgia, fever, skin lesions, which are similar to rheumatological diseases. The article presents a clinical observation of the classical type of Fabry disease with multiple organ manifestation, which required differential diagnosis with rheumatological diseases. Rheumatologists are specialists who are involved in the early diagnosis of Fabry disease, so they should have a high awareness of this sphingolipidosis.

Ligneous periodontitis exacerbated by Behçet's disease in a patient with plasminogen deficiency and a stop-gained variant PLG c.1468C > T: a case report.

BACKGROUND: Plasminogen serves as the precursor to plasmin, an essential element in the fibrinolytic process, and is synthesized primarily in the liver. Plasminogen activation occurs through the action of plasminogen activator, converting it into plasmin. This conversion greatly enhances the fibrinolytic system within tissues and blood vessels, facilitating the dissolution of fibrin clots. Consequently, congenital deficiency of plasminogen results in impaired fibrin degradation. Patients with plasminogen deficiency typically exhibit fibrin deposits in various mucosal sites throughout the body, including the oral cavity, eyes, vagina, and digestive organs. Behcet's disease is a chronic recurrent systemic inflammatory disease with four main symptoms: aphthous ulcers of the oral mucosa, vulvar ulcers, skin symptoms, and eye symptoms, and has been reported worldwide. This disease is highly prevalent around the Silk Road from the Mediterranean to East Asia. We report a case of periodontitis in a patient with these two rare diseases that worsened quickly, leading to alveolar bone destruction. Genetic testing revealed a novel variant characterized by a stop-gain mutation, which may be a previously unidentified etiologic gene associated with decreased plasminogen activity. CASE PRESENTATION: This case report depicts a patient diagnosed with ligneous gingivitis during childhood, originating from plasminogen deficiency and progressing to periodontitis. Genetic testing revealed a suspected association with the PLG c.1468C > T (p.Arg490*) stop-gain mutation. The patient's periodontal condition remained stable with brief intervals of supportive periodontal therapy. However, the emergence of Behçet's disease induced acute systemic inflammation, necessitating hospitalization and treatment with steroids. During hospitalization, the dental approach focused on maintaining oral hygiene and alleviating contact-related pain. The patient's overall health improved with inpatient care and the periodontal tissues deteriorated. CONCLUSIONS: Collaborative efforts between medical and dental professionals are paramount in comprehensively evaluating and treating patients with intricate complications from rare diseases. Furthermore, the PLG c.1468C > T (p.Arg490*) stop-gain mutation could contribute to the association between plasminogen deficiency and related conditions.

Glanzmann's thrombasthenia associated with gastrointestinal angiodysplasias successfully treated with bevacizumab.

Glanzmann's Thrombasthenia (GT) is a rare hemorrhagic condition caused by a platelet surface receptor disorder of the glycoprotein (GP) IIb/IIIa. Symptoms of GT are various forms of hemorrhages, such as purpura, epistaxis and menorrhagia. Gastrointestinal bleeding (GIB) is a rare expression of the condition and may occur due to traumas in the GI tract or as a consequence of gastrointestinal angiodysplasia (GIADs). In this case report, we present a middle-aged woman with recurrent GIB consequent to GIADs with persistent melena and iron deficiency anemia. After several unsuccessful therapeutic interventions, the patient was studied by the hereditary hemorrhagic telangiectasia's (HHT - Osler-Weber-Rendu disease) unit, where she received bevacizumab, showing a complete improvement in symptoms as well as a reduction in her GIADs. This case shows that bevacizumab could be a possible line of treatment for patients with coagulation disorders with GIADs.

The Hepatic Porphyrias: Revealing the Complexities of a Rare Disease.

The porphyrias are a group of metabolic disorders that are caused by defects in heme biosynthesis pathway enzymes. The result is accumulation of heme precursors, which can cause neurovisceral and/or cutaneous photosensitivity. Liver is commonly either a source or target of excess porphyrins, and porphyria-associated hepatic dysfunction ranges from minor abnormalities to liver failure. In this review, the first of a three-part series, we describe the defects commonly found in each of the eight enzymes involved in heme biosynthesis. We also discuss the pathophysiology of the hepatic porphyrias in detail, covering epidemiology, histopathology, diagnosis, and complications. Cellular consequences of porphyrin accumulation are discussed, with an emphasis on oxidative stress, protein aggregation, hepatocellular cancer, and endothelial dysfunction. Finally, we review current therapies to treat and manage symptoms of hepatic porphyria.

[The Ehlers Danlos syndrome : a rare disease although commonly suspected]. / Le syndrome d'Ehlers Danlos : une maladie rare fréquemment suspectée.

The Ehlers Danlos syndromes (EDS) are a heterogenous group of inherited connective tissue disorders characterized by generalized joint hypermobility and instability, tissue fragility and multiple functional disorders. The EDS hypermobility type (hEDS) is the most common but the mildest subtype of EDS and is defined by joint involvement. hSED diagnosis is based on clinical criteria because no genetic factors nor molecular basis have yet been identified. Since chronic pain constitutes one of hESD main symptoms, the diagnosis is frequently suspected although the syndrome is rare, with a prevalence estimated to be 1/10.000. An expert clinical evaluation is therefore necessary in order to establish an accurate diagnosis. This allows the implementation of physical therapy which is the only treatment that has proven efficacious in reducing joint instability, generalized pain and secondary osteoarthritis.

Les syndromes d'Ehlers Danlos (SED) sont un groupe hétérogène de maladies héréditaires du tissu conjonctif, caractérisées par une hypermobilité et une instabilité articulaires généralisées, une fragilité des tissus et de multiples troubles fonctionnels. La forme hypermobile du SED (hSED) est le sous-type le plus fréquent, mais le moins sévère des SED. Elle se présente essentiellement sous forme de manifestations articulaires. Le diagnostic du hSED repose sur des critères cliniques, aucun facteur génétique ni base moléculaire n'ayant été identifiés à ce jour. La douleur chronique étant l'un des symptômes principaux du hSED, le diagnostic est souvent évoqué alors que le syndrome est rare, la prévalence étant estimée à 1/10.000. Une expertise clinique est nécessaire afin d'établir un diagnostic correct. Ceci permet la mise en route d'une rééducation kinésithérapique, seul traitement ayant démontré son efficacité pour contrôler les symptômes et réduire l'instabilité articulaire et l'arthrose secondaire.

Serum alkaline phosphatase can be elevated in patients with hypophosphatasia due to liver disease.

BACKGROUND: Hypophosphatasia (HPP) is a rare inherited disorder caused by pathogenic loss-of-function variants in the ALPL gene, encoding the tissue-nonspecific isoenzym of alkaline phosphatase (ALP; TNSALP). Low serum ALP is the biochemical hallmark of HPP, but it is unknown whether ALP levels can increase due to concurring liver disease, which may lead to a missed diagnose of HPP. We present a patient with genetically confirmed HPP, who showed a transient increase of serum ALP levels due to alcohol-induced hepatitis. CLINICAL REPORT: A 71-year old man was seen at our Bone Center for surveillance of HPP. Serum ALP was always low (23 U/L; reference value: <115 U/L). During follow-up, his serum ALP increased (156 U/L, further rising to 204 U/L), with concomitantly elevated serum gamma-glutamyl transferase and transaminases, and a rise in bone specific ALP (18.7 µg/L; reference value: 5.7-32.9 µg/L). This was attributed to alcohol-induced hepatitis. After refraining from alcohol intake, both serum ALP and bone specific ALP levels returned to initial low levels (30 U/L and 4.3 µg/L respectively). CONCLUSIONS: We demonstrated the history of a 71-year old patient with HPP, presenting during routine follow-up with an elevated serum ALP level up to 204 U/L due to alcohol-induced hepatitis. This case illustrates that the diagnosis of HPP can potentially be missed when ALP levels are normal or elevated due to a concomitant liver disease.

Angiosarcoma in the breast: a population-based cohort from Sweden.

BACKGROUND: Breast angiosarcoma is a rare disease mostly observed in breast cancer (BC) patients who have previously received radiotherapy (RT). Little is known about angiosarcoma aetiology, management, and outcome. The study aim was to estimate risk and to characterize breast angiosarcoma in a Swedish population-based cohort. METHODS: The Swedish Cancer Registry was searched for breast angiosarcoma between 1992 and 2018 in three Swedish healthcare regions (population 5.5 million). Information on previous BC, RT, management, and outcome were retrieved from medical records. RESULTS: Overall, 49 angiosarcomas located in the breast, chest wall, or axilla were identified, 8 primary and 41 secondary to BC treatment. Median age was 51 and 73 years, respectively. The minimum latency period of secondary angiosarcoma after a BC diagnosis was 4 years (range 4-21 years). The cumulative incidence of angiosarcoma after breast RT increased continuously, reaching 1.4‰ after 20 years. Among 44 women with angiosarcoma treated by surgery, 29 developed subsequent local recurrence. Median recurrence-free survival was 3.4 and 1.8 years for primary and secondary angiosarcoma, respectively. The 5-year overall survival probability for the whole cohort was 50 per cent (95 per cent c.i., 21 per cent-100 per cent) for primary breast angiosarcoma and 35 per cent (95 per cent c.i., 23 per cent-54 per cent) for secondary angiosarcoma. CONCLUSION: Breast angiosarcoma is a rare disease strongly associated with a history of previous BC RT. Overall survival is poor with high rates of local recurrences and distant metastasis.

Vector autoregression: Useful in rare diseases?-Predicting organ response patterns in a rare case of secondary AA amyloidosis.

BACKGROUND: Statistical analyses of clinical data are a cornerstone in understanding pathomechanisms of disorders. In rare disorders, cross-sectional datasets of sufficient size are usually not available. Taking AA amyloidosis as an example of a life-threatening rare disorder resulting from of uncontrolled chronic inflammation, we propose techniques from time series analysis to predict organ response to treatment. The advantage of time-series analysis is that it solely relies on temporal variation and therefore allows analyzing organ response to treatment even when the cross-sectional dimension is small. METHODS: The joint temporal interdependence of inflammatory activity and organ response was modelled multivariately using vector autoregression (VAR) based on a unique 4.5 year spanning data set of routine laboratory, imaging data (e.g., 18F-Florbetaben-PET/CT) and functional investigations of a 68-year-old patient with multi-organ involvement of AA amyloidosis due to ongoing inflammatory activity of a malignant paraganglioma in stable disease for >20 years and excellent response to tocilizumab). RESULTS: VAR analysis showed that alterations in inflammatory activity forecasted alkaline phosphatase (AP). AP levels, but not inflammatory activity at the previous measurement time point predicted proteinuria. CONCLUSION: We demonstrate the feasibility and value of time series analysis for obtaining clinically reliable information when the rarity of a disease prevents conventional prognostic modelling approaches. We illustrate the comparative utility of blood, functional and imaging markers to monitor the development and regression of AA amyloidosis.