Spindle Cell Lipoma and Pleomorphic Lipoma in the Head and Neck: A Comprehensive Study of Six Cases With Review of Literature

Abstract

Background: Spindle cell lipomas (SL) and pleomorphic lipomas (PL) are rare variants of lipomas, occurring predominantly in the head and neck region. Laryngeal SL/PL is very uncommon and causes obstructive symptoms needing immediate intervention. These tumors are often challenging in radiology due to the admixture of elements and the presence of adipose tissue may help in diagnosis. From a surgeon's perspective, understanding the nuances of SL/PL is paramount. Histology is the gold standard for diagnosis; however, it often causes diagnostic challenges in biopsy. Method: A retrospective review of the clinical and pathologic features of archival cases of SL/PL was performed.

Results: A total of six cases of head and neck region SL/PL were identified. The age of patients ranged from 21 to 58 years and the male-to-female ratio was 5:1. The tumors were distributed in the nape of the neck (n=3), laryngeal region (n=2), and orbit (n=1). Histology in all the cases showed a low-grade neoplasm composed of a variable amount of spindle cells and adipose tissue. The stroma was myxoid in most cases. CD34 was diffusely positive in all the cases.

Conclusion: SLs are a rare and uncommon variant of lipoma with a predilection in the head and neck region. They are low-grade neoplasms with a propensity to recur after years. Having knowledge of this tumor can improve surgical outcomes and better patient care.

Keywords: cd34; head and neck; larynx; lipoma; molecular profile; spindle cell.

Figure 1. Radiology images

A. A well-defined lobulated encapsulated mass (block arrow) is seen in the subcutaneous plane in the upper back. Few hyperintense areas are seen on T1W sequences (white arrow) showing suppression suggestive of fat-containing areas. B. A relatively well-defined hypodense non-enhancing lesion is seen in the left pyriform sinus extending into the para-glottic space at the level of true and false cords without infiltration of the adjacent structures

Figure 2. Histomophology of spindle cell/pleomorphic lipoma

A. Scanner view showing a well-defined lesion composed of scattered adipocytes in a myxoid stroma. B. (x100 HE) Histology shows a moderately cellular tumor containing plump spindle cells with interspersed fat spaces and delicate capillaries in a prominent myxoid stroma. C & D. (x400 HE) Ropy/ ribbon-like collagen fibrils were seen in the tumor.

Figure 3. Histomorphology and immunohistochemistry of spindle cell/pleomorphic lipoma

A-C. (x400 HE) The tumor showed presence of scattered large, atypical cells with pleomorphic nuclei as well as multinucleated floret-like cells. D. (x400) By immunohistochemistry, the tumor was diffusely and strongly positive for CD34.