A 65 year old Caucasian male was admitted acutely complaining of generally feeling unwell with fever, painful skin swellings over his arms and legs, headache and epigastric pains. 
He had a complex 4 years history when he presented with intermittent fever and chills, arthralgia of large joints, painful skin nodules of arms and legs, dry cough, shortness of breath, redness of his right eye, painful right testicle, anorexia and weight loss of two months duration. He denied oral or genital ulcers. Over the ensuing two months he was extensively investigated to define the underlying disease.
The main abnormalities on previous investigations were as follows: 
Complete blood count: Hemoglobin 106 gram per litre, mean corpuscular volume (MCV) 97.5, erythrocyte sedimentation rate (ESR) 134 mm/Hr, C-reactive protein (CRP) 135 mg/dl (normal less than 3.5). Normal total white blood cell (WBC) count and differential. Rouleoux, oval macrocytes. Pseudo Pelger-Huet cells and occasional myelocytes on film. Platelet and reticulocyte counts were normal.
Liver function test: gamma-glutamyl transferase 172 (7-64 iu/l), alkaline phosphatase 399 (42-121 iu/l), albumin 16 (32-55 iu/l), bilirubin and alanine aminotransferase normal.
Urea 10.2 (3-6 mmol/l), creatinine137 (53-115 umol/l). Normal sodium and potassium.
Immunoglobulin (IG) G level was raised (polyclonal) 19.1 (8-18 gm/l). Normal IgM, IgA and IgE levels.
Chest X-ray: Bilateral patchy basal consolidation and mild bilateral pleural effusions which were confirmed on computerized tomographic scans.
Ultrasound scan of scrotal sac showed changes consistent with epididymo-orchitis.
CT scan of the abdomen: normal.
The following serological tests were done and found to be negative: Hepatitis B & C screen, HIV test, anti-nuclear antibodies, anti-DNA antibodies, rheumatoid factor, anti-cytoplasmic antibodies, anti-cardiolipin antibodies, Coomb's test, ASO titre, cryoglobulins, Brucella serology, complement levels, C1-esterase level.
Other negative tests done for a possible infective agent: malaria film, Brucella culture, Mantoux test, sputa for acid fast bacilli, leprosy nasal smears, urine microscopy.
Two skin biopsies were taken:
Sample 1: Summary of findings:
Skin showing extravasation of erythrocytes in the upper dermis. Deeper down there is a panniculitis, mainly of lobular type. The inflammation consists of histiocytic cells, lymphocytes, and granulocytes. There is a large vessel with thickened muscular wall containing granulocytes and lymphocytes. Picture of panniculitis with vasculitis. 
Sample 2: Summary of findings:
Skin fragment shows rather normal epidermis. Upper dermis shows extravasation of erythrocytes. Capillary blood vessels show sometimes thickened walls, containing leukocytes. Picture consistent with leucocytoclastic vasculitis.
Other biopsies taken and found to be negative/normal were:
Bilateral temporal artery biopsies
Conjuctival biopsy
Liver biopsy
Bronchoscopy and bronchoscopic samples
Bone marrow aspirate/biopsy: Unsuccessful initial attempt. Patient declined a repeat.
The patient was empirically treated with broad spectrum antibiotics, anti-malarial therapy followed by treatment for tuberculosis and brucellosis, without improvement.  Treatment with oral prednisolone 60 mg a day resulted in prompt improvement in his well-being, subsidence of his fever and normalization of his ESR. 
Over the subsequent years, he was maintained on prednisolone therapy. However, it became apparent that reducing his prednisolone dose or non-compliance on the patient's part resulted in the prompt recurrence of his painful nodular skin lesions, fever, arthralgia, urticarial facial swellings, lung infiltrates (pneumonitis), and increase in both C-reactive protein and ESR (above 100 mm/hr). His general condition usually worsened during these episodes, resulting in frequent hospital admissions. Unfortunately, high dose prednisolone led to the development of diabetes mellitus which necessitated using oral hypoglycemic agents. A brief trial of azathioprine as a steroid-sparing agent worsened his anemia and it was discontinued. 
Bone marrow examination at another hospital showed myelodysplasia but with no cytogenetic abnormalities.
Over the years, in addition to myelodysplasia, he was given various diagnoses including Behcet's disease, anti-phospholipid syndrome, and pyrexia of unknown origin responsive to steroids.
These included warfarin for two previous confirmed episodes of deep venous thrombosis (left leg and right leg), glibenclamide for diabetes mellitus and prednisolone 10 mg per day.
He looked ill and pale. He had an urticarial right peri-orbital swelling as well as several tender 0.5-1.0 cm subcutaneous nodules felt over the extensor and flexor surfaces of both upper and lower limbs. There was no lymph node enlargement and no oral, respiratory, cardiovascular, abdominal, neurological, musculoskeletal or genital abnormalities.
Hemoglobin 9.1, MCV 101.3, WBC 9.9, platelets 152, ESR 133, CRP 103, international normalized ratio (INR) 3.1.
Renal and liver function and urinalysis were normal.
Chest X-ray - normal.
Electrocardiogram - normal.
The patient was given intravenous hydrocortisone 100 mg three times a day with a quick resolution of his symptoms and disappearance of his painful skin swellings. Within few weeks his ESR dropped to 33 mm/hr. On reducing his steroid dose to 10 mg per day of prednisolone, his facial urticaria recurred and he developed a left sided pleuritic chest pain. A chest radiograph confirmed a new left basal infiltrate and an associated small effusion. These again promptly resolved (within 48 hours) on increasing his steroid dose. Cyclosporin was then added as a possible steroid-sparing agent. 
A repeat bone marrow examination was performed.
Salient features of bone marrow aspirate: multilineage dysplasia involving the granulocytic, erythroid and megakaryocytic cell lines.
Erythroid dysplastic features including: increased mitosis, nuclear lobulation and extensive vacuolation.
Myeloid dysplastic features were found in at least 19% of the precursors. These features included pseudo Pelger-Huet anomaly, misshapen nuclei and increased vacuolation. Blasts made up about 2% of all nucleated cells. Normal amounts of stainable iron were present with normal numbers of sideroblasts. Pathologically ringed sideroblasts were not present.
Salient features of bone marrow core biopsy:
Pronounced hypercellularity (98-100%). The tri-lineage dysplasia was confirmed; the presence of micromegakaryocytes, the megalobastoid erythropoiesis and  the presence of numerous mitotic figures. Especially noteworthy was the abnormal localization of immature myeloid precursors (ALIP). Lymphocytes and plasma cells were normal. Reticulin fibrosis was mildly increased and thinned-out bony trabeculae confirmed osteoporosis. Abnormal non-haemopoietic cells and/or granulomata were not present.