Abstract
Pseudogout, also known as calcium pyrophosphate dihydrate deposition disease (CPPD) with giant cell reparative granuloma (GCRG) of the temporal bone is a rare disease, which is very easy to misdiagnose. When two diseases occur simultaneously, the pathological tissue of diseases is closely associated, which complicates clinical representation and causes enormous difficulty in diagnosis and treatment. We report a case of CPPD of the temporomandibular joint accompanied by surrounding GCRG of temporal bone in a 62-year-old male.
1
Introduction
CPPD is mainly caused by the deposition of calcium pyrophosphate dihydrate in the articular cartilage. Although CPPD has an unknown etiology, it is currently considered as a metabolic disorder . GCRG is a trauma- or infection-related reactive reparative for giant cell lesion . While CPPD mainly affects fibrocartilage and hyaline cartilage of the joints, GCRG most commonly occurs in the mandible, followed by the sphenoid bone, craniofacial bones, and the bones of hands and feet . This report describes the diagnosis and treatment of a rare case of CPPD of the temporomandibular joint accompanied by surrounding GCRG of the temporal bone.
2
Case report
The patient was a 62-year-old male. Five years ago, the anterior part of his right external auditory canal started to swell without evident cause, and there was no local pain and limitation of mouth opening. Hearing in his right ear started to decline in the past two months, which was not associated with tinnitus, ear pain, or otorrhea. He had no history of high blood pressure, high cholesterol, high uric acid, chronic extremity pain, gout, or arthritis. His blood glucose was normal and there was no history of thyroid disease, systemic lupus erythematosus, or other autoimmune diseases. The patient had no previous major head and neck trauma and surgery. He had a 20 year history of using his right side teeth to bite a rigid plastic rod (as the former owner of a plastics factory, he had to bite the small plastic rod product to determine the product’s quality). Such habit of long-term biting hard plastic might cause chronic damage to his right temporomandibular joint and temporal bone due to repeated loading. The patient consumed 100 packets of cigarettes per year in the past 20 years and drank 100 g of white wine per day in the past 10 years.
A 3 × 3 cm mass detected anterior to the patient’s right ear (the root of the zygomatic arch) was hard, without tenderness, and was immobile. There was atresia of his right external auditory canal but there was no discharge. Pure tone audiometry indicated conductive hearing loss of the right ear, with an average hearing threshold ~ 50 dB. His mouth opening was normal, and the occlusion of upper and lower teeth was good. Routine blood tests, serum electrolytes (urate, magnesium, calcium, and phosphorus), and thyroid function tests were all normal. Rheumatoid factor and anti-DNA antibody were both negative. The urinary hydroxyproline level and phosphate clearance were also normal.
CT scan revealed large calcified clumps enveloping the condylar process, surrounded by a soft tissue mass (slightly higher than the density of skeletal muscle) ( Fig. 1 ). T1WI and T2WI of preoperative MRI examination showed a low signal of the soft tissue mass around the calcified clump of right temporomandibular joint ( Fig. 2 ). On T1WI of enhanced MRI, the mass was significantly enhanced, while without enhancement the calcification displayed a low signal. The zygomatic process and squamous part of the right temporal bone, the petrous apex, and the wall of tympanic cavity were damaged from erosion, resulting in thinning and partial loss of the bone. The soft tissue mass intruded forward and upward into the right middle cranial fossa, upward into the tympanic cavity wrapping the ossicles, backward into the external auditory canal, and forward into the infratemporal fossa, with a clear boundary.
Under general anaesthesia, tumor resection was carried out via the infratemporal fossa approach. Intraoperative exploration showed that the temporomandibular joint capsule was covered by a large amount of a white amorphous calcified mass. There was a dark brown mass around the calcified mass and partially destroyed zygomatic bone, ossicular chain, middle skull base and temporal bone. The pathological tissue and destroyed bone were cut out, and the surgical cavity was filled with ipsilateral abdominal adipose tissue. Frozen section intraoperative pathology of the white calcified mass indicated CPPD.
Under hematoxylin and eosin staining, the calcified tissue inside the temporomandibular joint capsule presented purple-blue granules and small diamond crystals, surrounded by a fibrous stromal reaction, while a small number of nuclei were seen in giant cells of the granuloma tissue ( Fig. 3 ). The interstitial cells were spindle-shaped, accompanied by collagen fiber proliferation, reactive new bone formation, and inflammatory cell infiltration. A 25 degree polarization angle and weakly positive birefringence were observed with the white slide of calcium pyrophosphate crystals under a polarized light microscope ( Fig. 4 ).
There was no improvement in the patient’s hearing, but the other symptoms disappeared. One year follow-up showed no symptoms, and physical examination indicated no sign of relapse.
2
Case report
The patient was a 62-year-old male. Five years ago, the anterior part of his right external auditory canal started to swell without evident cause, and there was no local pain and limitation of mouth opening. Hearing in his right ear started to decline in the past two months, which was not associated with tinnitus, ear pain, or otorrhea. He had no history of high blood pressure, high cholesterol, high uric acid, chronic extremity pain, gout, or arthritis. His blood glucose was normal and there was no history of thyroid disease, systemic lupus erythematosus, or other autoimmune diseases. The patient had no previous major head and neck trauma and surgery. He had a 20 year history of using his right side teeth to bite a rigid plastic rod (as the former owner of a plastics factory, he had to bite the small plastic rod product to determine the product’s quality). Such habit of long-term biting hard plastic might cause chronic damage to his right temporomandibular joint and temporal bone due to repeated loading. The patient consumed 100 packets of cigarettes per year in the past 20 years and drank 100 g of white wine per day in the past 10 years.
A 3 × 3 cm mass detected anterior to the patient’s right ear (the root of the zygomatic arch) was hard, without tenderness, and was immobile. There was atresia of his right external auditory canal but there was no discharge. Pure tone audiometry indicated conductive hearing loss of the right ear, with an average hearing threshold ~ 50 dB. His mouth opening was normal, and the occlusion of upper and lower teeth was good. Routine blood tests, serum electrolytes (urate, magnesium, calcium, and phosphorus), and thyroid function tests were all normal. Rheumatoid factor and anti-DNA antibody were both negative. The urinary hydroxyproline level and phosphate clearance were also normal.
CT scan revealed large calcified clumps enveloping the condylar process, surrounded by a soft tissue mass (slightly higher than the density of skeletal muscle) ( Fig. 1 ). T1WI and T2WI of preoperative MRI examination showed a low signal of the soft tissue mass around the calcified clump of right temporomandibular joint ( Fig. 2 ). On T1WI of enhanced MRI, the mass was significantly enhanced, while without enhancement the calcification displayed a low signal. The zygomatic process and squamous part of the right temporal bone, the petrous apex, and the wall of tympanic cavity were damaged from erosion, resulting in thinning and partial loss of the bone. The soft tissue mass intruded forward and upward into the right middle cranial fossa, upward into the tympanic cavity wrapping the ossicles, backward into the external auditory canal, and forward into the infratemporal fossa, with a clear boundary.
