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Year : 2014  |  Volume : 8  |  Issue : 1  |  Page : 8-10

Pattern of adipose tissue tumors in Ahmadu Bello Universty Teaching Hospital, Zaria, Nigeria

Department of Pathology, Ahmadu Bello University Teaching Hospital, Zaria, Kaduna State, Nigeria

Date of Web Publication18-Sep-2014

Correspondence Address:
Umar Mohammed
Department of Pathology, Ahmadu Bello University Teaching Hospital, Zaria - 810 001, Kaduna State
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0331-3131.141022

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Background: Adipose tumors are the most common soft tissue tumors in humans. The reported incidence of lipoma is probably less than the actual incidence because of its insidious growth pattern and minimal associated symptoms.
Objective: The objective of this study is to document the pattern of these tumors in a tertiary hospital in Northern Nigeria.
Materials and Method: This is a retrospective study of all diagnosed adipose tissue tumor over a 10-year period (January 2002 to December 2011), in the Department of Pathology, Ahmadu Bello University Teaching Hospital. Tissue biopsies fixed in 10% formalin and stained routinely with hematoxylin and eosin were studied. Biodata and sites of involvement were retrieved from patients' requisition cards.
Results: Four hundred and three adipose tissue tumors were diagnosed during this period. Three hundred and ninety-five (98.0%) of the tumors were benign, while 8 (2.0%) were malignant. The male to female distribution was 197 and 206, respectively. Patients ages ranged from 3 months to 75 years with a peak age distribution in the fifth decade (23.6%). The most common site of involvement was the trunk (38.0%), followed by the head and neck region (21.3%) and lower limbs (17.4%). Conventional lipoma was the most common benign tumor, accounting for 328 cases (81.4%), while myxoid liposarcoma was the most common malignant tumor with 4 cases (1.0%).
Conclusion: Adipose tissue tumors are not uncommon in our setting and accounted for 6.0% of all tumors seen within the study period. There is a slight female preponderance and the trunk is the most common site of involvement. Benign tumors formed the bulk of lesions recorded.

Keywords: Adipose tissue tumors, histological type, site, age, gender

How to cite this article:
Mohammed U, Samaila MO, Abubakar M. Pattern of adipose tissue tumors in Ahmadu Bello Universty Teaching Hospital, Zaria, Nigeria. Ann Nigerian Med 2014;8:8-10

How to cite this URL:
Mohammed U, Samaila MO, Abubakar M. Pattern of adipose tissue tumors in Ahmadu Bello Universty Teaching Hospital, Zaria, Nigeria. Ann Nigerian Med [serial online] 2014 [cited 2021 Apr 18];8:8-10. Available from: https://www.anmjournal.com/text.asp?2014/8/1/8/141022

   Introduction Top

Adipocytic tumors account for the largest single subtype of soft tissue tumors. The benign subcutaneous lipoma contributes the highest incidence in this group, with liposarcoma being the most common primary soft tissue malignancy. [1] The majority of fatty neoplasms arise in childhood with the exception of lipoblastoma and the occasional lipoma. [1] Lipomas occur most commonly in adult females, with some reported cases in childhood and adolescence. [2] This study aims to document the histological pattern and frequency of occurrence of adipose tissue tumor in our environment.

   Materials and Methods Top

This is a retrospective descriptive study of adipose tissue tumor diagnosed in the Department of Pathology, Ahmadu Bello University Teaching Hospital, Zaria, over 10 years period (January 1, 2002 to December 31, 2011).

All tissues had been previously fixed in formalin. The hematoxylin and eosin stained slides were retrieved in each case and reviewed microscopically by the authors. All other stained slides were also retrieved and studied microscopically by the authors. Clinical information such as age, sex, and site of affectation in each case where extracted from the respective patient request cards. Results are presented in frequency distribution tables. Cases with missing tissue block and slides were excluded from the study.

   Result Top

Four hundred and three cases were analyzed, and of these 395 (98.0%) were benign and eight (2.0%) malignant [Table 1].
Table 1: Age distribution of adipocytic tumors

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There were 197 males and 206 females with a slight female preponderance (M:F ratio 1:1.1) [Table 2]. The ages of the patients ranged from 3 months to 75 years, with a peak age in the fifth decade [Table 1].
Table 2: Sex distribution of adipocytic tumors

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The benign tumors comprised of conventional lipoma 328 (81.4%), fibrolipoma 62 (15.4%), and angiolipoma 2 (0.5%). Others tumors such as hibernoma and myolipoma accounted for 1 (0.3%) case each, and were seen in the patients within the age range of 40 and 49 years; all in male patients [Table 2]. Lipoblastoma accounted for 1 case (0.3%) and was seen in the age range of 10-19 years.

Of the 8 malignant tumors, myxoid liposarcoma accounted for 4 cases (1.0%), well differentiated - 3 cases (0.7%) and pleomorphic - 1 case (0.3%) [Table 2]. Malignant tumors occurred mostly in those aged 40-59 years, with 3 cases (1.0%). Overall, the trunk was the most common anatomic site afflicted with adipose tissue tumor with 153 cases (38.0%) [Table 3].
Table 3: Anatomical distribution of adipose tissue tumor

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   Discussion Top

Adipose tissue tumors are the commonest soft tissue tumor in humans. [3] The actual incidence of lipoma is probably much higher than the reported incidence. This is not surprising, considering that most lipomas have insidious growth with localized mass effect. Many also only require a physician's intervention when they reach large sizes and cause cosmetic problems or complications due to anatomical location. [1],[4] Majority of the adipose tissue tumors are benign and accounted for 98.0% of all our cases. This observation is similar to studies by Seleye-Fubara and Etebu [5] and Weiss and Goldblum [4] We recorded 5.5% cases of adipose tissue tumors in the first two decades of life, and this is comparable to other reports. [1],[3],[4],[5]

Ancillary diagnostic techniques such as immunohistochemistry and electron microscopy have only a limited or occasional role, since most cases are diagnosed on light microscopy alone. [1],[4]

The slight female preponderance in this study is in consonance with other studies. [1],[3],[5],[6] A few studies, however, have documented a higher prevalence in males. [4],[7]

Conventional lipoma was the most common benign adipocytic tumor seen in this study accounting for 82.8% of cases; followed by fibrolipoma. This finding is in keeping with other similar studies. [1],[3],[7] Hibernoma, an unusual tumor of brown fat accounted for 0.3% of our cases. This tumor is thought to morphologically mimic the brown fat of hibernating animals. Since its first description in 1906, only a few case reports and small series have described this rare, somewhat peculiar, tumor. [1],[3],[4],[8] The solitary lipoblastoma in this series occurred in the thigh of an 11 year old female. Lipoblastoma (lipoblastomatosis) is almost exclusively seen in infants and young children below the age of 5 years, though occasional cases are seen in adolescents and young adults with a predilection for the proximal portion of the lower and upper extremities. [1],[3],[9]

Adipocytic tumors favoured the trunk 35.1%, and head and neck 20.0%. This anatomical distribution corroborates earlier reports. [1],[3],[4],[5],[7] Adipose tissue is quantitatively an important component of normal breast tissue, however, intra-mammary lipoma is rare. We recorded (4%) cases in the breast, which underscores the rarity of this lesion in the breast. They usually occur as solitary tumors, though multiple lesional masses may be encountered. [10],[11]

Liposarcoma is a common sarcoma of adults and commonly appear in those aged between 40 and 60 years, and rarely in children. [12] Our cases (1.2%) occurred within this same age group, while 3 cases (0.7%) were seen in the age group 20-39 years. Myxoid liposarcoma was the most common in our series, although other reports have documented it as the second most common. [1],[3],[13],[14]

   Conclusion Top

Adipose tissue tumors are common in our environment. Benign conventional lipoma is the most common adipose tissue tumors with a predilection to the trunk. It displayed a slight female preponderance with peak distribution in the fifth decade of life.

   References Top

1.Fletcher CD. Soft tissue tumours. In: Fletcher CD, editor. Diagnostic Histopathology of Tumours. 2 nd ed. Boston: Churchill Livingstone; 2000. p. 1474-85.  Back to cited text no. 1
2.Malone M. Soft tissue tumours in childhood. Histopathology 1993;23:203-16.  Back to cited text no. 2
3.Rosai J. Soft tissue tumours. In: Rosai and Ackerman's Surgical Pathology. 10 th ed., Vol. II. New York, NY, USA; Mosby an Imprint of Elsevier; 2011. p. 2140-5.  Back to cited text no. 3
4.Weiss SW, Goldblum JR. Benign lipomatous tumours. In: Enzinger FM, Weiss SW, editors. Soft Tissue Tumours. 4 th ed. Boston: Churchill Livingstone; 2001. p. 571-694.  Back to cited text no. 4
5.Seleye-Fubara D, Etebu EN. Adipose tissue tumour in Port Harcourt: A ten year review. Sahel Med J 2005;8:92-4.  Back to cited text no. 5
6.Leffert RD. Lipomas of the upper extremity. J Bone Joint Surg Am 1972;54:1262-6.  Back to cited text no. 6
7.Rydholm A, Berg NO. Size, site and clinical incidence of lipoma. Factors in the differential diagnosis of lipoma and sarcoma. Acta Orthop Scand 1983;54:929-34.  Back to cited text no. 7
8.Furlong MA, Fanburg-Smith JC, Miettinen M. The morphologic spectrum of hibernoma: a clinicopathologic study of 170 cases. Am J Surg Pathol 2001;25:809-14.  Back to cited text no. 8
9.Collins MH, Chatten J. Lipoblastoma/lipoblastomatosis: a clinicopathologic study of 25 tumors. Am J Surg Pathol 1997;21:1131-7.  Back to cited text no. 9
10.Rosen PP. Benign mesenchymal neoplasms. In: Rosen's Breast Pathology. 2 nd ed. New York, NY, USA: Lippincott Williams and Wilkins; 2001. p. 786-7.  Back to cited text no. 10
11.Drijkoningen M, Tavassoli FA, Magro G, Eusebi V, Devouassoux-Shisheboran M, Bellocq JP, et al. Messenchymal tumours of the breast. In: Tavassoli FA, Devilee P, editors. World Health Organization Classification of Tumours: Pathology and Genetics of Breast and Female Genital Tract. Lyon: IARC Press; 2005. p. 89-98.  Back to cited text no. 11
12.Rosenberg AE. Bones, joints and soft-tissue tumours. In: Kumar V, Abbas A, Fausto N, editors. Robbins and Cotran Pathologic Basis of Disease. 8 th ed. Philadelphia, PA. USA: Saunders Elsevier; 2010. p. 1249-50.  Back to cited text no. 12
13.Enzinger FM, Winslow DJ. Liposarcoma. A study of 103 cases. Virchows Arch Pathol Anat Physiol Klin Med 1962;335:367-88.  Back to cited text no. 13
14.Antonescu C, Ladanyi M. Myxoid liposarcoma In: Fletcher CD, Unni KK, Mertens F, editors. World Health Organization Classification of Tumours: Pathology and Genetics of tumours of Soft Tissue and Bone. Lyon: IARC Press; 2002. p. 40-3.  Back to cited text no. 14


  [Table 1], [Table 2], [Table 3]

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