|IMAGES IN RHEUMATOLOGY
|Ahead of print publication
Role of fine-needle aspiration cytology in the diagnosis of erosive polyarticular tophaceous gout
Sonu Kalyan1, Anuj Dhull2, Priyanka Khuttan3
1 Department of Pathology, Kalpana Chawla Government Medical College, Karnal, Haryana, India
2 Good Hopes Diagnostic Center, Karnal, Haryana, India
3 Department of Radiology, All India Institute of Medical Science, New Delhi, India
|Date of Submission||17-Nov-2019|
|Date of Acceptance||25-May-2020|
Source of Support: None, Conflict of Interest: None
Keywords: Fine-needle aspiration cytology, tophaceous gout, urate crystals
A 50-year-old diabetic gentleman presented with numerous periarticular and soft-tissue swellings for past 7 years which had progressively increased in the number and size over the past 4–5 years. Physical examination confirmed multiple firm-hard nodular, swellings involving bilateral elbow joints, interphalangeal joints of the hand and feet, bilateral knee joints, along with tenderness, erythema, and swelling of the surrounding soft tissues. Some of these had ulcerated with the presence of pus and chalky white material present on the surface [Figure 1]a-d].
|Figure 1: (a-d) Soft-tissue swellings of the hand, elbow, and feet with multiple periarticular soft-tissue swellings with ulcerative lesions present on the right foot (covered with antiseptic dressing), (e) radiographs of the hand with multiple periarticular soft-tissue swellings with nonmarginal erosive arthropathy, (f) Polarized photomicrographs of fine-needle aspiration smears at ×400 having strongly birefringent needle-shaped crystals of monosodium urate and (g) is Giemsa-stained smear at ×400 showing numerous needle-shaped refractile crystals of monosodium urate along with the foreign-body type of multinucleated giant cell|
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With the provisional diagnosis of neurofibromatosis, fine-needle aspiration cytology (FNAC) was ordered, to find blood mixed chalky white aspirate from three different sites, which on microscopy revealed clumped aggregates interspersed with refractile needle-shaped crystals and numerous multinucleated foreign-body giant cells [Figure 1]g. Polarized microscopy confirmed strongly birefringent needle-shaped crystals suggestive of chronic tophaceous gout [Figure 1]f.
Further, the patient had elevated serum uric acid level (8.6 mg/dl) and fasting blood glucose level (230 mg/dl), although renal function tests were normal. Radiographs of elbow joint, hand, knee joint, and feet suggested extensive periarticular soft-tissue swellings with nonmarginal erosive destruction of underlying bone [Figure 1]e.
| Discussion|| |
Gout is a metabolic disorder of purine metabolism that results from long-standing hyperuricemia and urate crystal deposition in various tissues. It is characterized by the recurrent attacks of red, tender, hot, and swollen joints due to hyperuricemia that results from considered that diet and coexisting metabolic syndrome. Gout is associated with increased frequency of obesity, chronic kidney disease, hypertension, Type 2 diabetes, dyslipidemias, cardiac diseases, stroke, and peripheral arterial disease. As in the present case, the patient was known to have Type II diabetes.
Poor treatment leads to tophi from the precipitation of uric acid in the periarticular and subcutaneous tissues, particularly in the cooler parts of the body around the olecranon process, knee joint, volar aspect of the forearm, Achilles tendon, and helix of the ear.
Oftentimes, serum uric acid may be low or normal during an attack, more so in diabetic due to the uricosuric action of increased blood glucose levels. Lower levels of uric acid are also seen in alcoholics.,
The differential diagnoses of chronic tophaceous gout include rheumatoid arthritis, osteoarthritis, sarcoidosis, tumor calcinosis, and tophaceous pseudogout. Tumoral calcinosis and tophaceous pseudogout yield intensely basophilic, calcified material on FNAC in contrast to needle-like crystals observed in gouty tophi. On the other hand, tumoral calcinosis deposits are amorphous and lack a crystalline structure. The calcium pyrophosphate dihydrate crystals of pseudogout are smaller, rhomboid, or needle-shaped and show weakly positive birefringence as opposed to monosodium urate (MSU) crystals, which are longer and show strong-negative birefringence., It is noteworthy that crystals of MSU can be preserved in the alcohol-fixed cytological smears to prevent loss during tissue processing. Thus, FNAC is a valuable inexpensive, minimally invasive, and convenient tool in the diagnosis of such cases.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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