Journal of Head & Neck Physicians and Surgeons

CASE REPORT
Year
: 2021  |  Volume : 9  |  Issue : 1  |  Page : 64--66

A recurrent hibernoma in neck: An extremely rare entity


Shirish Chandanwale, Rumaanah Khan, Arpana Dharwadkar, Ruchi Randive 
 Department of Pathology, Dr. D. Y. Patil Medical College, Pune, Maharashtra, India

Correspondence Address:
Shirish Chandanwale
75/1 + 2/1, Krishna Appt, New Sangvi, Pune - 411 027, Maharashtra
India

Abstract

Lipomatous lesions are very commonly encountered in clinical practice. Although they are commonly encountered in the third and fourth decades, they can occur at any age. Clinically, they present as slowly painless growing mass commonly in subcutaneous tissues. Clinically and radiologically, they are difficult to differentiate from other lipomatous lesions. The four morphological variants have been identified. Hibernoma cells are key to diagnosis. Hibernomas do not have malignant potential or metastatic ability. However, local recurrence is known to occur and is extremely rare. Wide local excision with negative margins is the key to prevent further recurrence.



How to cite this article:
Chandanwale S, Khan R, Dharwadkar A, Randive R. A recurrent hibernoma in neck: An extremely rare entity.J Head Neck Physicians Surg 2021;9:64-66


How to cite this URL:
Chandanwale S, Khan R, Dharwadkar A, Randive R. A recurrent hibernoma in neck: An extremely rare entity. J Head Neck Physicians Surg [serial online] 2021 [cited 2021 Dec 5 ];9:64-66
Available from: https://www.jhnps.org/text.asp?2021/9/1/64/319742


Full Text



 Introduction



Subcutaneous lipomatous lesions are commonly encountered in clinical practice. Hibernomas are rare subtype of the benign lipomatous neoplasms originating from brown fat. It accounts for <1.6% of benign lipomatous tumors and 1.1% of all adipocytic neoplasms.[1] They commonly occur in the third and fourth decades. Literature review reveals a slight female preponderance.[2],[3] Majority are subcutaneous and only 10% are intramuscular The most common reported sites of hibernoma are interscapular region, axilla, neck, thigh, mediastinum, and retroperitonium.[1],[4],[5]

It poses a diagnostic challenge, as clinical and radiological findings are nonspecific and difficult to differentiate from atypical lipomatous lesions and well-differentiated liposarcoma. Although hibernoma does not undergo malignant transformation and produce metastasis. Local recurrence is documented and extremely rare. Very few cases of recurrence have been reported.[4],[5],[6] Wide local excision with negative margin is a key. We report one such case of 45-year-old female with the recurrence of hibernoma in the neck.

 Case Report



A 45-year-old woman came with complaints of a slow growing, painless mass on the right lateral side neck for 4 months. There was no history of trauma or any similar swelling elsewhere in the body. She gave a history of some operative surgery at the same site 3 years ago. The details of which she did not have. On physical examination, subcutaneous soft tissue mass measuring 4 cm × 4 cm was palpable on the right lateral neck. The mass was well delineated and soft to firm. The 2 cm scar was seen on skin at the same site.

Routine laboratory parameters were within normal limits. Ultrasonography of neck showed subcutaneous soft tissue, well circumscribed, hyperechoic lesion measuring 3.5 cm × 4 cm. It was free from underlying muscles and structures. A diagnosis of lipoma was suggested.

The patient underwent surgical resection. A yellowish tumor mass with thin capsule measuring 4 cm × 3.5 cm was received for histopathological examination. At places, brown ting was appreciated [Figure 1]. Adequate tissue sections were formalin fixed and paraffin processed. The 3 μ thick sections were cut and stained with hematoxylin and eosin. Microscopy of stained sections showed a tumor mass comprised mixture of mature adipocytes and hibernoma cells with multivacuolated and granular eosinophilic cytoplasm Very few cells showed univacuolated cytoplasm. Nucleus was placed centrally. Stroma was scanty and showed fibrocollagenous tissue with congested capillaries [Figure 2]a and [Figure 2]b. There were no nuclear atypia or mitotic figures. A final histopathology diagnosis of hibernoma was made.{Figure 1}{Figure 2}

 Discussion



Hibernoma is a rare, benign soft-tissue tumor of brown fat origin.[1] Although hibernomas can occur anywhere in the body, the common anatomic locations are interscapular region, axilla, thigh, neck, mediastinum, and retroperitoneum.[5] In contrast, largest case series with 170 patients of hibernoma by Furlong et al. observed thigh as the most frequent location followed by upper extremity, trunk, neck, and abdominal cavity.[6] Some reports suggest that males are commonly affected than females.

Hibernomas are most commonly diagnosed postoperatively on histopathological examination. Ultrasonography findings are nonspecific, as happened in our case. Many times they raise a diagnostic challenge on imaging studies. They are difficult to differentiate from other lipomatous lesions and well-differentiated liposarcoma. Recent studies have proposed that advanced imaging such as magnetic resonance imaging (MRI) can further guide preoperative diagnosis. A well-differentiated liposarcoma on MRI show irregular capsule with thick septations and decreased vascularity compared with hibernomas.[7]

Four histological variants have been described: (1) typical hybernoma which show mixture of eosinophilic and multivacuolated and univaculoated cells. (2) Myxoid variant show loose basophilic matrix. (3) Spindle cell hibernoma has features of spindle cell lipoma and hibernoma. (4) Lipoma like variant in which only scattered hibernoma cells are seen with mature adipocytes. In our case, it was typical hybernoma which showed mixture of multivacuolated and cells with eosinophilic granular cytoplasm with very few univacuolated cells. Many mature adipocytes were also seen. Complete excision is indicated. Incomplete resection of the tumor can lead to recurrence which was seen in our case. Wide local excision with negative margins is the key to prevent further recurrence.

 Conclusion



Hibernoma is a rare benign tumor, originating from brown fat. Majority are subcutaneous. They need to be differentiated from atypical lipoma and well-differentiated liposarcoma. They are often diagnosed postoperatively. Computed tomography findings are not specific. Advanced imaging such as MRI can guide further preoperative diagnosis. They do not have malignant potential or produce metastasis. Local recurrence is extremely rare and is known to occur. Wide local excision with negative margins is the key to prevent further recurrence.

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.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

Disclosure

This material has never been published and is not currently under evaluation in any other peer-reviewed publication.

Ethical approval

The permission was taken from the Institutional Ethics Committee before starting the project. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed consent

Informed consent was obtained from all individual participants included in the study.

References

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