TUMOR-LIKE SOFT TISSUE SWELLING OF THE DISTAL PHALANX DUE TO CALCIUM PYROPHOSPHATE DIHYDRATE CRYSTAL DEPOSITION

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1 1428 BRIEF REPORT TUMOR-LIKE SOFT TISSUE SWELLING OF THE DISTAL PHALANX DUE TO CALCIUM PYROPHOSPHATE DIHYDRATE CRYSTAL DEPOSITION H. RALPH SCHUMACHER, JR., HUGH BONNER, JOHN J. THOMPSON, WALTER L. KESTER, and JOHN J. BENNER, IV Extraarticular deposits of calcium pyrophosphate crystals are rare and have been restricted largely to paraarticular tendons, ligaments, and bursae (1,2). This report describes a patient with a tumor-like swelling of the distal phalanx that proved to be due to a mass of calcium pyrophosphate crystals. Case report. A 68-year-old white man noted the gradual development of a firm swelling of the pulp of his right index finger about 1% years prior to evaluation in February The swelling slowly increased and was occasionally associated with 2-3-day episodes of erythema and tenderness over the mass. Aspirin, 600-1,800 mg/day, helped the painful episodes. He denied any pain at the index distal interphalangeal joint or any other parts of the hands. He recalled occasional knee pain on ambulation since age 18; however, he had no knee swelling. Since age 64, he had known hypertension, which was currently being treated with Dyazide (50 mg triamterene, 25 mg hydrochlorothiazide) 1 tablet twice a day and Aldomet (methyldopa 250 mg) twice a day. H. Ralph Schumacher, Jr., MD: Professor of Medicine, University of Pennsylvania School of Medicine, and Director, Rheumatology-Immunology Center, Veterans Administration Medical Center, Philadelphia; Hugh Bonner, MD: Department of Pathology, Chester County Hospital, West Chester, Pennsylvania; John J. Thompson, MD: Kaiser Permanente Regional Laboratory, Clackamas, Oregon (formerly Resident in Pathology, University of Pennsylvania Hospital); Walter L. Kester, MD: Department of Medicine, Chester County Hospital; John J. Benner, IV, MD: Department of Orthopedic Surgery, Chester County Hospital. Address reprint requests to H. Ralph Schumacher, MD, Director of Rheumatology-Immunology Center, Veterans Administration Medical Center, University and Woodland Avenues, Philadelphia, PA Submitted for publication February 24, 1984; accepted in revised form June 3, Physical examination revealed a blood pressure of 130/80. The pulp of the right second finger was tensely swollen with a firm, nontender mass. The examination results were unremarkable otherwise except for a hard nodule on the right side of the thyroid. Complete blood count and blood chemistry values were normal except for a serum uric acid level of 10.1 mg/dl. Other laboratory values were serum calcium 8.9, phosphate 3.4, alkaline phosphatase 10.4 units/liter (normal), serum iron 51 mg/dl, and total iron binding capacity 303 mg/dl. Rheumatoid factor and antinuclear antibody test results were negative, as were the results of a urinalysis. Radiographs of the right second finger (Figure 1) showed fluffy calcification overlying the right second distal phalanx and replacing much of the finger pulp. There was slight narrowing and sclerosis of the distal interphalangeal (DIP) joint. Joint space narrowing, sclerosis, and spur formation were seen at the second DIP joint of the right hand, the third metacarpophalangeal joints of the right and left hands, the second and third DIP joints of the left hand, and the third and fifth proximal interphalangeal joints of the left hand. There were specks of calcification at the left second DIP joint. The results of a chest radiograph were normal. An electrocardiogram showed a suspected old inferior wall myocardial infarction thyroid scan identified a cold nodule in the lower pole of the right lobe. Surgical excision of the finger mass was performed under local anesthesia. When an unusual crystalline deposit was found, it was submitted to the first author for further study. Light microscopic examination of the deposit revealed multiple foci of basophilic material, shown to Arthritis and Rheumatism, Vol. 27, No. 12 (December 1984)

2 BRIEF REPORTS 1429 A Figure 1. A, Lateral roentgenogram of calcification in index finger pulp with slight sclerosis, narrowing, and irregularity of the distal interphalangeal joint. B, Posteroanterior roentgenogram showing same findings. Calcification overlaps the bone so that a clear delineation of cortex from soft tissue calcification is not possible. B contain positively birefringent long and short rod-like crystals when viewed with compensated polarized light (Figure 2). Rare crystals also appeared to be negatively birefringent. Giant cells and histiocytes surrounded the clumps of crystals. There were areas of chondrometaplasia often within or around the calcifications. A portion of the paraffin block was dissolved and the crystal-containing tissue was fixed and embedded as previously described for transmission electron

3 1430 BRIEF REPORTS Figure 2. Hematoxyphilic material with clear rod-like crystals (white in this figure) from the distal phalanx. Note central cells with suggestion of chondrometaplasia. Viewed with polarized light (hematoxylin and eosin stained, original magnification x 120). microscopy (3,4). Many electron-dense foamy crystals consistent in ultrastructural appearance with calcium pyrophosphate dihydrate crystals (CPPD) (4) were noted (Figure 3). In addition, there were some clear crystal-shaped clefts from which other crystals might have been dislodged or dissolved and rare clusters of tiny apatite-like, needle-shaped crystals in the body of the mass. Qualitative, elemental analytic studies were performed on the foamy, electron-dense crystals using a spot size of 0.75~ diameter and 200-second exposures with a lithium-drifted silicon energy dispersive x- ray detector (Kevex) interphased with a multichannel analyzer attached to the Zeiss EM 10 transmission electron microscope. These showed calcium : phosphorus ratios calculated at , which is consistent with the expected ratio for calcium pyrophosphate of 1.0. One clump of apatite-like needles had a calcium:phosphorus ratio of approximately l.6: l. Postoperatively, the finger did well except for some residual stiffness. A hand radiograph revealed some residual calcification at the distal phalanx and loss of bone mineral consistent with some erosion of the phalanx by the mass. Two months after this surgery, the thyroid nodule was excised and found to be a follicular adenoma with a large zone of calcification. This contained no crystals when viewed with compensated polarized light. At this time, the patient s serum uric acid level was 9.3 and his blood urea nitrogen level was 26. Postoperativdy he had simultaneous sudden onset of pain and swe. ling of the right first metatarsophalangeal (MTP) and right knee joints. Neitherjoint was aspirated, but both responded well to treatment with a combination of indomethacin, 25 mg 3 times a day, and colchicine. Radiographs of both knees were obtained and showed chondrocalcinosis of the articular cartilages and menisci. Foot roentgenograms showed only degenerative changes at the first MTP joints. He was briefly treated with probenecid, but this and the antiinflammatory agents were discontinued after several weeks. Allopurinol therapy, 150 mg per day, was started, and tie continued taking Dyazide and methyldopa. In early 1983, he was found to have a nasopharyngeal carcitioma. He was treated with 5,500 rads as a curative procsdure. The patient was contacted in June I983 and was doing well, although he had just recovered from another attack of right first MTP joint pain and swelling.hat had responded to indomethacin. He was still takirg allopurinol, 150 mg/day, and Dyazide. His serum ur c acid level was 6.2 mg/dl. Discussion. The major interest in this case is the unusual extrzarticular presentation of a massive deposit of calcium pyrophosphate crystals in a patient not known to have articular calcium pyrophosphate deposition. All previously identified deposits of CPPD have been associated with peripheral joints, bursae, tendons (l), cr in tissues around the spine (9, including the dura mater (6). A tophus-like nodule containing CPPD crystals has been reported associated with flexor tendon i at a DIP joint (7). The tumor-like mass of CPPD in the distal phalanx of our patient could well have originated from the adjacent DIP joint although this was not clinically appreciated. This would continue to support the importance of some unique factor in articular, tendon, and bursa1 tissues that might be needed for CPPD deposition. Tumor-like masses of CPPD crystals have been reported to arise from other joints and have also been associated with chondrometaplasia of soft tissues (&lo), as noted in our patient. This chondrometaplasia may also have contributed to lccal connective tissue changes favoring CPPD deposition. Crystals have been seen in joints with apparent osteochondromas (1 l), but whether the crystals actually arose in the metaplastic cartilaginous tissue is not known. In our patient we must note that, in addition, there may haire been other crystals present that were lost in the routine processing of the specimen in waterbased fixativc before we examined the tissue. That

4 BRIEF REPORTS 1431 Figure 3. Electron micrograph of tissue from the distal phalanx showing foamy, electron-dense crystals consistent in appearance with calcium pyrophosphate crystals, and white holes from which crystals are dislodged (original magnification X 48,000). urate could have been present is suggested by the hyperuricemia, subsequent podagra, and the infrequent negatively birefringent crystals seen in the tumor-like mass. Urate tophi are known to calcify. Although their calcifications have not been studied systematically, it has been supposed that they are most probably due to apatite. Some rare apatite was also noted in the mass studied. Urate or apatite and CPPD crystals have previously been documented together in joint fluids (I 1-13). Acknowledgments. The authors gratefully acknowledge the help of Mary Ellen Maguire in the preparation of the manuscript and the technical assistance of Susan Rothfuss, Marie Sieck, and Gilda Clayburne. REFERENCES 1. McCarty DJ: Calcium pyrophosphate crystal deposition disease: pseudogout: articular chondrocalcinosis, Arthritis and Allied Conditions. Ninth edition. Edited by DJ McCarty. Philadelphia, Lea & Febiger, 1979, pp Gerster J-C, Lagier R, Boivin G: Olecranon bursitis related to calcium pyrophosphate dihydrate crystal deposition disease: clinical and pathologic study. Arthritis Rheum 25: , 1982

5 1432 BRIEF REPORTS 3. Schumacher HR: Articular cartilage in the degenerative arthropathy of hemochromatosis. Arthritis Rheum 25: , Schumacher HR: Ultrastructural findings in chondrocalcinosis and pseudogaut. Arthritis Rheum 19: , Bywaters EGL, Hamilton EBD, Williams R: The spine in idiopathic hemochromatosis. Ann Rheum Dis 30: , Grahame R, Sutor DJ, Mitchenor MB: Crystal deposition in hyperparathyroidism. Ann Rheum Dis , Leisen JCC, Austad ED, Bluhm GB, Sigler JW: The tophus in calcium pyrophosphate deposition disease. JAMA 244: , Pntzker KPH, Phillips H, Luk SC, Koven IH, Kiss 4, Houpt JB: Pseudotumor of temporomandibular joint: destructive calcium pyrophosphate dihydrate arthropathy. J Kheumatol 3:70-81, Ling P, Mi rphy WA, Kyriakos M: Tophaceous pseudogout. Radiology 138: , Gibson JP, Koenigk WJ: Pseudogout in a dog. J Am Vet Med Assoc 161: , Wise CM, Wheeler GE, lrby WR, Schumacher HR: Synovial o jteochondromatosis and pseudogout. J Rheumatol (in press) 12. Stockman A, Darlington LG, Scott JT: Frequency of chondroac:ilcinosis of the knees and avascular necrosis of the femoral head in gout: a controlled study. Ann Rheum Di:, 39:7-11, Schumachcr HR, Gordon GV, Paul H, Reginato A, Villaneuva T, Cherian V, Gibilisco P: Osteoarthritis, crystal deposition and inflammation. Semin Arthritis Rheum 11: , 1981