HIBERNOMA O F THE ADRENAL A. LEE McGREGOR

Senior Surgeon, Johannesburg General Hospitul

IN May 1952 Mrs. E. J. Visser aged 46 was admitted to Ward 19 of the Johannesburg General Hospital complaining of increasing headache and breathless- ness. The blood pressure was 220/140 mm. Hg. Investigation proved the case to be a typical one of essential hypertension in which surgery was indicated.

On the 15th May, 1952 the Smithwick thoraco-lumbar ganglionectomy combined with splanchnicectomy was carried out on the right side. Routinely the adrenal gland is investigated. In this case it was found to be very much larger than usual extending over a surface area almost the size of a fist. It was browny yellow in colour and finger like processes extended from it into the surrounding tissues and over the posterior surface of the liver. The neurectomy was then carried out.

It was decided to remove the tumour as its nature was uncertain. Pheochromocytoma was considered and Dr. Devitt, senior anaesthetist to the Hospital who was in charge of the anaesthesia, was asked to be prepared for dramatic alterations in blood pressure. The canary yellow colour of the normal adrenal was not apparent. The removal of the gland was not associated with any very dramatic rise in blood pressure. At the commencement of the operation it was 190/130 mm. Hg. When the adrenal was being handled the pressure rose to 250/180 mm. Hg. Vegelysin given intravenously dropped the pressure to 150/120 mm. Hg. On two subsequent occasions the pressure rose to the previous high level. The patient left the table with a pressure of 115/95 mm. Hg. Convalescence was uneventful.

Description of the tumour: Measurements after fixation were 11 crns. by 10 crns. Weight 62 grams.

Pathology: Dr. B. J. P. Becker of the S.A.I.M.R. reports:-

vascular reticulated stroma arranged in lobules. polygonal cells rich in cytoplasm and well defined rounded nuclei.

Sections of this tumour tissue from the region of the adrenal show a richly The lobules consist of large

The cell

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cytoplasm exhibits a finely to coarsely vacuolated granular cytoplasm. These cells have the characteristic histological appearance of "moruloid" cells. Many of them contain fine brown granules of a lipofuscin pigment. From these cells a transition can be traced to adult fat cells-the fatty vacuoles enlarge and coalesce and the nucleus becomes eccentric and flattened. (See Fig. 1 ) .

FIG. 1 Haematoxylin and Eosin magnified

x 1600.

I am of the opinion that the tumour is a benign embryonic pigmented lipoma

The second stage was carried out on 29th May, 1952. The adrenal on the It was not interfered with. The blood

She was

or hibernornu. This type of lipoma manifests a recurrent tendency.

left was identical to that on the right. pressure rose at one stage to higher figures than at the first operation. discharged well on the 12th June, 1952.

The surprising nature of this finding stimulated an interest in the matter.

Etiology: Geschickter ( 1934) discusses the histogenesis and etiology of lipomatous tumours in general and comments on the important contributions which have been made to knowledge of the subject. He points out that the location and age of onset of the neoplasms in both benign and malignant tumours show that developmental processes are of first importance.

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The processes are the genetic pattern of tissue development and the influence of endrocrine hormones. Half of the benign solitary lipomas occur in the neck, on the back, and between the shoulders in an interscapular location. In these regions there occurs in the embryo a mass of vascular lymphoid tissue which includes many fat cells. Extending from the posterior triangle into the back and under the scapulae there is found in some of the lower animals a fat storage mechanism known as the hibernating gland. It is considered that the vascular lymphoid tissue alluded to above is the remnant of this gland and that the frequency of the lipomatous tumours in this region results from hormonal activation of this tissue after puberty.

Geschickter goes on to say that lipomatous tumours seem to follow the same distribution as the lymph sacs which are found in the lower part of the neck of the human embryo and in the lumbar region. Thus fatty tumours are common also in the retroperitoneal tissues around the kidneys and in the groin and thigh.

Pathology: Inglis ( 1927)3 reviewed the literature relating to the hibernating gland. He quotes Shattock (1908-9)6 who described two types of adipose tissue. In the one type illustrated by ordinary connective tissue, fat is deposited in droplets. These ultimately coalesce into a single fat globule. In the other variety of adipose tissue the fat, deposited as single droplets, retains that form which histologically allies this cell group to that of a ductless gland. In hibernating animals this type of fat constitutes hibernating tissue and it is reserved whilst the fat of connective tissue is absorbed as required by the metabolic needs of the host. Shattock interprets these facts as indicating a physiological as well as a histological specialization. Inglis found this type of tissue in the sites mentioned above and also on the upper surface of the diaphragm and in the peri-renal and retroperitoneal tissues.

Brines and Johnson (1949)l state the first hibernoma was described in 1905 and that to the time of writing 9 cases were reasonably well authenticated and 7 others were possibly acceptable. The neck, back, and axilla were the common sites. The authors point out the difficulty of distinguishing true hibernomas from some other types of fatty tumours such as a typical lipomas and low grade lipo- sarcomas. They found no case of malignant hibernoma. The case they described occurred in the right scapular region, was partially encapsulated and was yellowish changing to reddish brown in colour. It was composed of large cells which varied from 20 to 50 u/c in diameter with centrally placed nuclei.

Kittle, Boley, and Schafer4 report the unique case of a large intrathoracic hibernoma removed from the left side of the chest. Comment: It is apparent from the foregoing that hibernoma is one of the rarest types of tumour which occurs in the human body, furthermore no case of malignancy has been described. The case reported here is unique in two respects: (a) It was bilateral and symmetrical. (b) It was so closely related to the adrenal gland that together the gland and the tumour formed a single structure.

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Hibernomas do not constitute a threat per se to the host and should only be removed for cosmetic reasons or if from an accident of situation they compress or impede important organs or structures.

My thanks are due to Dr. B. J. P. Becker of the South African Institute for Medical Research, for the pathology and microphotograph.

BIBLIOGRAPHY

1. BRINES, Osborne A., and JOHNSON, M. Harvey, 1949: Hibernoma, a special fatty tumour. The American Journal of Pathology. Vol. xxv: 467-475.

2. GESCHICKTER, Charles F. 1934: The American Journal of Cancer. Vol. 21:

3. INGLIS, Keith 1927: “The so called interscapular gland, and tumours arising therein.” Journal of Anatomy. Band LXI: 452-466.

4. KITTLE, C. F., BOLEY, J. O., and SCHAPER, P. W. 1951: Resection of a intrathoracic hibernoma. The Journal of Thoracic Surgery. Vol. 19: 830-836.

5. SHATTOCK, S. G. 1908-9: Proceeding of Royal Society of Medicine. Vol. 2: Part 3: Pathological Section: 208.

617-641.

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