Eosinophilic granuloma of the temporal bone- its clinical manifestations and managementJyotsna M Kirtane1, MV Kirtane2, PP Karnik2
1 Department of Paediatric Surgery, J. J. Group of Hospitals, Bombay., India
2 E.N.T. Department, K.E.M. Hospital, Pared, Bombay-400 012, India
Eosinophilic granuloma is a variety of Histiocytosis-X. Its etiology is unknown. When it involves the temporal bone it may mimic chronic otitis media, or a mastoid abscess, very often leading to an erroneous diagnosis. Its X-ray appearance and histopathology are characteristic. Infiltration with eosinophils and histiocytes is a constant feature. Very good results are achieved with surgery accompanied by radiotherapy. In this series of 3 patients, one patient presented with facial paralysis and another one with bilateral post-auricular swellings. The first 2 cases were diagnosed only after surgery and histopathological examination of the tissue removed, while the third case was diagnosed pre-operatively on clinical and radiological findings.
Eosinophilic granuloma is a disease o unknown etiology. It is usually classifies as a variety of histiocytosis X. The other two diseases included in this group are Hand-Schuller-Christian disease, and Letterer Siwe disease. Since Hand's article in 1893, several reports have appeared it the literature describing conditions which have one feature in common, namely proliferative, granulomatous lesion characterized by histiocytes with accumulate; of lipid, giant cells, and the characteristic eosinophils.
The term eosinophilic granuloma was first introduced by Lichtenstein and Jaffe  in 1940. Farber  in 1941 arrived at the conclusion that eosinophilic granuloma, Hand-Schuller-Christian disease, and Letterer Siwe disease, represent variations in degree, stage of involvement, and localization of the same basic disease process. It was Lichtenstein who coined the term histiocytosis X, which is used today for this disease.
The three variants of histiocytosis X have related manifestations; but are symptomatically and prognostically different ,,,,, Letterer Siwe disease is usually a rapidly fatal process occurring most frequently in children below the age of 3 years. The main clinical findings are enlargement of the spleen, liver and lymph nodes; a secondary anemia, purpuric cutaneous eruptions, destructive skeletal lesions, especially in the skull, and a downhill febrile course.
Hand-Schuller-Christian disease was originally described as a triad syndrome manifested by skull destruction, exophthalmos, and diabetes insipidus. The latter two components are the result of destructive involvement of the sphenoid bone. In present day descriptions, the exophthalmos, and diabetes insipidus need not occur. 
Eosinophilic granuloma occurs as single or multiple lesions of bone destruction. It is seen more commonly in children or young adults, although, it may be found at all ages. Other sites like lung and the gastrointestinal tract may also be affected. These cases of primary soft tissue involvement appear to be a variant of Hand-Schuller-Christian disease rather than true eosinophilic granuloma. 
An eosinophilic granuloma of the temporal bone is uncommon. It may present as otorrhoea, polyp in the external canal, otalgia or post-auricular swelling. The areas of destruction seen in the X-ray may lead the physician into making an erroneous diagnosis of the more common disease, namely chronic otitis media with a cholesteatoma or tuberculous mastoiditis. The presence of a post-aural swelling may hence be mistaken for a mastoid abscess.
The prognosis of eosinophilic granuloma, with treatment with steroids, surgery and deep X-ray therapy, is far more optimistic than the other two variants of histiocytosis X.
A boy of 5 years was admitted in February 1972 with a painful left post-aural swelling of 2 weeks duration. He had otorrhoea on the left side for 2 years. He was active and alert, but apprehensive. There was a polypoidal mass occupying the left external auditory canal. The post-aural swelling was markedly tender. The X-ray of the mastoids showed an area of destruction in the left mastoid, and hence a diagnosis of a left ear cholesteatoma with mastoid abscess was made see [Figure 1] on page 54A. A left radical mastoidectomy was done. The mastoid was seen to be filled with pale, yellowish pink granulation tissue. The posterior canal wall had been destroyed and the middle ear was also involved. The malleus, incus and superstructure of the stapes were also destroyed by the disease. There was no evidence of cholesteatoma.
On histopathological examination a diagnosis of eosinophilic granuloma was made see [Figure 2] on page 54A.
The wound healing was good. Subsequently the entire skeletal system was examined but showed no other lesion. The patient was given radiotherapy post-operatively. The total dose given was 800 r.
This patient is being regularly followed over the last 5½ years. He has a well epithelialized mastoid cavity, no local recurrence, or evidence of a lesion appearing anywhere else on the body.
A boy aged 4 years, came to the hospital in July 1972 with a painful right post-aural swelling and a facial paralysis of 7 days duration. He gave a history of right otorrhoea for the last one year.
He was afebrile, alert, but would not allow a proper examination of the ear due to pain. His X-ray showed an osteolytic lesion in the right mastoid. Under general anaesthesia the mastoid was explored. It was seen to be filled with pale granulation tissue which also extended into the middle ear, destroying the ossicles. At this stage we thought the lesion was due to tuberculosis, as this disease is fairly common in our country, and is associated with a typically pale, unhealthy granulation. tissue and facial palsy. The facial nerve in the horizontal part and at the second bend was found to be exposed and covered with granulation tissue. This granulation tissue was carefully removed with minimal handling of the nerve. The posterior canal wall was destroyed by the disease. A radical mastoidectomy was done.
The histopathological examination of the granulation tissue, however, showed the structure of eosinophilic granuloma. The patient was given radiotherapy with a dose of 800 r. The healing of the cavity was satisfactory. By the end of 6 weeks, the facial nerve function had recovered.
This patient did not show a bony lesion anywhere else on the body. He has been coming for regular follow up examinations for the last 5 years. There is no evidence of recurrence or appearance of new lesions.
A 3½ year old boy was admitted to the hospital in September 1974 with painful bilateral post-aural swellings of 3 weeks' duration. There was a history of an over-enthusiastic relative holding the boy by his ears and lifting him off the ground, while playing with the child, immediately prior to the appearance of the swellings. A diagnosis of infected hematoma was made. Incision and drainage of the swellings were done and the underlying tissue was taken for histopathological examination. This turned out to be a necrotic tissue, and gave no indication of the underlying pathology. After 2 weeks, the post-aural incisions had healed well. However, the external canals of both the sides were now found to be occluded by polypoidal masses with discharge. The X-ray showed punched out osteolytic lesions bilaterally. Hence a clinical diagnosis of eosinophilic granuloma was made. The right mastoid was again explored. The granulomatous tissue, pale, yellowish pink in colour filled the cavity, and having destroyed the posterior canal wall, had also invaded the middle ear and the external auditory canal. The malleus, incus and superstructure of the stapes were destroyed by the disease. The facial nerve canal was intact. This granulation tissue was scooped out as much as possible, and the wound was closed with a pack inside the cavity. The pack was brought out through a meatoplasty in the external canal. The histopathological examination confirmed the diagnosis.
The left ear was not treated surgically. Radiotherapy in a dose of 600 r. was given to each ear. One month pest-operatively the patient had a fairly clean and dry mastoid cavity on the right side. On the left side, the polypoidal mass in the external canal had disappeared and the ear had become dry.
Of the 3 classical variants of histiocytosis X, eosinophilic granuloma is a comparatively benign disorder. According to Lichtenstein,  the pathological evidence now available clearly demonstrates "that the condition represents the pathologic expression of an early, rapidly developing reaction to the etiologic agent, whatever it may ultimately prove to be." He favours the theory of viral infection as bouts of fever and night sweats are sometimes associated with the appearance of fresh lesions. In eosinophilic granuloma, the lesions begin in the marrow and gradually erode the cortex.  In majority of cases, the disease process remains localized, but occasionally, the process seems to fade into a more disseminated form of the disease.
Isolated lesions in the temporal bone are rare, and should be viewed with suspicion, as these may represent an early stage of a more diffuse disease process.
Clinically, pain is a very characteristic symptom. This may be associated with a swelling, otorrhoea and deafness. Symptoms due to erosion of the structures within the temporal bone may also be seen. The facial nerve canal may be eroded. Though erosion. of the labyrinth has been reported , such involvement is rare, suggesting that the bony labyrinth is extremely resistant to invasion by the granulomatous tissue.
The X-ray pictures in eosinophilic granuloma characteristically show punched out areas of bone destruction.
Thus, in a given case, with a combination of symptoms like pain, otorrhoea, deafness and post-aural swelling, and an osteolytic lesion in the X-rays, it is obvious why a mistaken diagnosis of mastoiditis with abscess is commonly made. In 2 of our cases, we made the above mistake pre operatively. In the third case, a pre-operative diagnosis of eosinophilic granuloma was made, because we were put on guard by the lesion being bilateral and the external canal showing pale yellowish granulation tissue. The ultimate diagnosis is always by a biopsy. A thorough check of the entire skeletal system was mad( in the three cases (2 cases post-operatively, one case pre-operatively) but fortunately for the patients, failed to reveal any other lesion.
The granulomatous tissue has a pale yellowish appearance. Microscopically it shows sheets or strands of large round histiocytes accompanied by eosinophil, and polymorphs. Giant cells may also be present. See [Figure 2] on page.
The lipidization of the histiocytes which may sometimes be seen in chronic form probably represents secondary changes. 
There is uniformity of opinion regarding the use of radiotherapy in eosinophilic granuloma. ,, However, many case: being diagnosed as mastoiditis are subjected to surgery first, the real diagnosis being revealed after microscopic examination of the tissue removed.
Lichtenstein  has advocated curettement and radiotherapy. He also mentions that spontaneous regression or even, disappearance has been demonstrated.
The 3 cases treated by us were all males. Their ages were 6, 4 and 32 years. All the 3 cases presented with a postaural abscess, and were subjected to surgery. Radiotherapy was given postoperatively.
In all our cases, the posterior wall of the external auditory canal and the middle ear were eroded, and hence a radical mastoidectomy was done in all cases. In the third case, where the lesion was bilateral, the left side was not operated but subjected to radiotherapy only.
We had no case where the labyrinth was eroded. In case of facial nerve involvement, careful removal of the granulation tissue from around the exposed nerve, with minimal handling of the nerve is advisable. In our second case, the granulation tissue around the nerve was carefully removed. The nerve sheath however was not incised to decompress the nerve. Six weeks post-operatively, the facial nerve function had fully recovered.
The first two patients are coming to us for regular check-ups over the past 5 years. Careful observation is essential as the temporal bone lesion may have been an early manifestation of a more diffuse disease process which may make its appearance later. Both the patients have a well epithelized mastoid cavity and no evidence of skeletal disease. The third case is also being observed.
We thank the Dean, K. E. M. Hospital Bombay-400 012 for permitting us to report the hospital data.
[Figure 1], [Figure 2]