Intramuscular spindle cell lipoma: Case report and review of the literature

Spindle Cell Lipoma Occurring in the Submandibular Space: Fifth Case Reported along with a Concise Review of the Literature

Spindle cell lipoma (SCL) is an uncommon histological variant of lipoma that accounts for 1.5% of all adipose tumors. It rarely occurs in the oral cavity. The most common sites of involvement are the buccal mucosa, tongue, lip, alveolar mucosa, gingiva, and palate. Submandibular space is a very rare site of occurrence for SCL. When occurs in this site, SCL mainly involves the 4th-7th decade with a female predominance. Due to wide communications of submandibular space, the actual extent and appearance of the lesions present here gets masked up especially those involving the deeper tissues leading to an inaccurate diagnosis. Wide overlap of clinical and histopathological features of SCL to other clinical pathologies leads to a challenging task for the clinicians to reach an accurate diagnosis. To our knowledge, only four cases of intraoral SCL involving the submandibular region directly or indirectly have been reported in the literature. Here we represent another rare case of SCL in an 18-year-old male patient along with a concise review of the literature. This case appears to be quite rare due to its location (submandibular space), age, and sex of the patient (18/M).

Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma With Features Mimicking Spindle Cell Lipoma

Atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDL) and spindle cell lipoma are lipomatous tumors with distinct clinical, molecular, and prognostic features. Although histological and immunophenotypic features can overlap between ALT/WDL and spindle cell lipoma, the oncogenesis and clinical behavior are markedly different. In borderline cases, molecular analysis for MDM2 or CDK4 amplification can aid in distinguishing ALT/WDL from spindle cell lipoma. Although dedifferentiated liposarcoma has been reported to harbor both MDM2 amplification and loss of the RB1 region, we are not aware of a reported RB1 loss in well-differentiated ALT/WDL. In this article, we present a 69-year-old woman with a lipomatous tumor in the gluteal region that histologically, immunohistochemically, and molecularly mimicked spindle cell lipoma (with positive immunohistochemical staining for CD34 and loss of the RB1 gene region), yet harbored amplification of MDM2 and CDK4 confirmed by fluorescence in situ hybridization, supporting classification as ALT/WDL. This case strengthens the argument that in atypical clinical contexts, molecular studies for MDM2/CDK4 should be considered in tumors resembling spindle cell lipoma.

Pleomorphic lipoma: A gentle giant of pathology

Pleomorphic lipoma is a relatively rare adipocytic neoplasm, occurring predominantly in elderly males in the subcutaneous tissues of the neck or shoulder. To the best of our knowledge, only five cases have been reported in which the lesion was intramuscular. We hereby report a case of a 60-year-old female patient, presenting with an intramuscular, posterior shoulder mass. The aspirate showed a giant cell-rich lesion, admixed with short, plump-looking, spindly cells. There was no overt evidence of malignancy; however, the cell cytology was sufficiently atypical to warrant concern. Subsequent excision revealed a classical pleomorphic lipoma on histology with no evidence of malignancy. CD34 staining by immunohistochemistry further supported the diagnosis. Differential diagnosis and the cytological diagnostic pitfalls of pleomorphic lipomas have been discussed with a review of the literature.

Intramuscular spindle cell lipoma of the deltoid: a case report

Introduction

Spindle cell lipoma is an uncommon adipocytic tumor. Intramuscular lesions of this tumor are very rare. In this report, we describe a case of a patient with intramuscular spindle cell lipoma localized in a deltoid.

Case presentation

A 58-year-old Japanese man visited us because of a soft tissue mass on the lateral aspect of the left shoulder that had been noticed 2 years prior. The spherical tumor, which measured 5cm×4cm, was elastic and firm on palpation and immobile. Magnetic resonance imaging revealed that the lesion was localized in the left deltoid muscle. A needle biopsy was performed to make a histological diagnosis. With a pre-operative diagnosis of intramuscular lipoma, we removed the tumor with the patient under general anesthesia. The tumor was removed with surrounding musculature and fascia. The pathological diagnosis was intramuscular spindle cell lipoma in the left deltoid muscle.

Conclusions

There are several kinds of lipomas. Spindle cell lipoma is a relatively rare variant (1.5% of all adipocytic neoplasms) that is histologically distinct and characterized by the replacement of mature fat by a mixture of mature adipocytes and undifferentiated spindle cells. There are only five other reported cases of intramuscular spindle cell lipoma in the literature, to our knowledge. The case of our patient is very interesting, as to date there have been few reported patients with a diagnosis of an intramuscular spindle cell lipoma in a deltoid.

Electronic supplementary material

The online version of this article (doi:10.1186/s13256-014-0509-0) contains supplementary material, which is available to authorized users.

Intramuscular dendritic fibromyxolipoma in a 24-year-old male: A case report and review of the literature

Dendritic fibromyxolipoma (DFML) is an uncommon, benign soft tumor that usually arises in the subcutis. To date, ~24 cases of DFML have been reported in the literature and only one of these has been in the muscle. The present study reports the case of a 24-year-old male with a slow-growing, painless mass located deep in the triceps brachii in the left shoulder region. The mass was 14.0×8.5×8.0 cm in size, with well-circumscribed margins. Microscopically, the resected mass was characterized by a proliferation of small spindle or stellate cells, prominent abundant myxoid stroma with ropey collagen bundles and admixed mature adipose tissue. Further immunohistochemical staining indicated that the spindle and stellate cells were reactive with cluster of differentiation 34, vimentin and B-cell lymphoma-2, but not with smooth muscle actin and desmin. Fluorescence in situ hybridization showed that the tumor cells did not have the DDIT3 alteration or amplification of MDM2. The tumor was confirmed to be a DFML due to the typical histological, immunophenotypic and genetic findings. To date, subsequent to 4 years of clinical follow-up, there is no sign of recurrence or metastasis. The present study reports a case of DFML in the youngest known patient, and is the second reported case of an intramuscular DFML occurring in the triceps brachii in the left shoulder region. The study discusses the clinicopathological features and the differential diagnosis of DFML, with a review of the literature.

An unusual and spectacular case of spindle cell lipoma of the posterior neck invading the spinal cervical canal and posterior cranial fossa

The authors describe the first case of spindle cell lipoma of the posterior neck invading the upper cervical spinal canal and the posterior cranial fossa. Spindle cell lipoma is an extremely rare variant of benign lipoma. It usually occurs as a solitary subcutaneous well-circumscribed lesion in the posterior neck or shoulders of adult men. Local aggressiveness is unusual. This 61-year-old man presented with an increased left cerebellar syndrome and headaches. He also had a posterior neck tumefaction, which had been known about for a long time. Computed tomography and MR imaging studies revealed a voluminous mass extending to the upper cervical canal and posterior cranial fossa and eroding the neighboring bones. The lesion was well delimited, and contrast enhancement was intense and heterogeneous. The tumor, which had initially developed under the muscles of the posterior neck, was totally resected. Histological assessment revealed numerous fat cells with spindle cells secreting collagen. The large size of the tumor and the submuscular location, bone erosion, and compression of the CNS were unusual in this rare subtype of benign adipose tumor. Its presentation could simulate a sarcoma.

Well-differentiated spindle cell liposarcoma ('atypical spindle cell lipomatous tumor') does not belong to the spectrum of atypical lipomatous tumor but has a close relationship to spindle cell lipoma: clinicopathologic, immunohistochemical, and molecular analysis of six cases

Well-differentiated spindle cell liposarcoma represents a rare atypical/low-grade malignant lipogenic neoplasm that has been regarded as a variant of atypical lipomatous tumor. However, well-differentiated spindle cell liposarcoma tends to occur in subcutaneous tissue of the extremities, the trunk, and the head and neck region, contains slightly atypical spindled tumor cells often staining positively for CD34, and lacks an amplification of MDM2 and/or CDK4 in most of the cases analyzed. We studied a series of well-differentiated spindle cell liposarcomas arising in two female and four male patients (age of the patients ranged from 59 to 85 years). The neoplasms arose on the shoulder, the chest wall, the thigh, the lower leg, the back of the hand, and in paratesticular location. The size of the neoplasms ranged from 1.5 to 10 cm (mean: 6.0 cm). All neoplasms were completely excised. The neoplasms were confined to the subcutis in three cases, and in three cases, an infiltration of skeletal muscle was seen. Histologically, the variably cellular neoplasms were composed of atypical lipogenic cells showing variations in size and shape, and spindled tumor cells with slightly enlarged, often hyperchromatic nuclei. Multivacuolated lipoblasts were present in three neoplasms. Focal myxoid stromal changes were seen in three cases. Immunohistochemically, CD34 was at least focally positive in all cases, whereas scattered tumor cells only showed a nuclear expression of MDM2 in two neoplasms. FISH analysis revealed a deletion of the Rb-1 gene in all six cases, whereas no MDM2/CDK4 amplification was identified in all cases tested. Follow-up information was available in four cases (range from 4 to 24 months), and revealed a local recurrence in one case. Although well-differentiated spindle cell liposarcoma and atypical lipomatous tumor behave clinically similar, it can be speculated on the basis of clinicopathologic and molecular findings that well-differentiated spindle cell liposarcoma may constitute an independent entity rather than a morphologic variant of atypical lipomatous tumor, and may represent the atypical/low-grade counterpart of spindle cell lipoma.

Intramuscular lipoma of the supraspinatus causing impingement syndrome

Impingement syndrome is a common ailment of the shoulder, particularly in individuals who perform repetitive overhead activities, such as athletes and laborers. Patients typically report progressive shoulder pain often exacerbated by flexion and abduction and may demonstrate a classic painful arc of motion. This article describes a case of a 45-year-old man with signs and symptoms consistent with impingement syndrome. Workup revealed a well-circumscribed, homogeneous lesion within the supraspinatus muscle on magnetic resonance imaging. The patient underwent uncomplicated marginal excision of the mass with a final diagnosis of benign lipoma. Lipomas represent one of the most common soft tissue tumors, although there are no reports of an intramuscular supraspinatous lipoma causing impingement syndrome. In our case, there were no findings on history, physical examination, or radiographs that would place neoplasm high on a differential. Magnetic resonance imaging provided the crucial information necessary to narrow the differential diagnosis and formulate a preoperative plan. Marginal resection of the mass was curative in this patient, as he remained pain free and regained excellent motion postoperatively.

Endotracheal spindle cell lipoma presenting as a chronic cough

An elderly gentleman with a chronic cough was found to have a large midtracheal lesion on computed tomography scan. Endotracheal extirpation with an electrocautery snare successfully removed the lesion. Histologic and immunohistochemical analyses revealed the lesion to be a spindle cell lipoma. We provide herein the case presentation and management, the differential diagnosis, and an overview of spindle cell lipoma.

Infiltrating intramuscular spindle cell lipoma of the face

Spindle cell lipoma is a benign lipomatous tumor, which usually arises on the back of the neck, shoulder or upper back of males in the third to seventh decade of life. We report herein an unusual infiltrating intramuscular spindle cell lipoma arising in the nose of a 53-year-old man. The patient presented with a 0.5-cm 'cyst' of the nose, just above the right alar crease, which was removed. Four years later, the lesion recurred and was re-excised. Histologically, a proliferation of mature adipocytes, ropey collagen fibers and spindle cells within a myxoid stroma was present in the subcutaneous tissue and infiltrated between skeletal muscle fibers. Nine cases of intramuscular spindle cell lipoma with histological examination have previously been reported and have involved the oral cavity and muscles of the extremities. To our knowledge, this is the first report of an infiltrating intramuscular spindle cell lipoma arising on the face.

Spindle cell lipoma of the floor of the mouth: Report of a case

Spindle cell lipoma is a benign tumour composed by: (1) mature fat cells; (2) spindle cells; (3) a myxoid matrix separated by thick bands of birefringent collagen. Only 14 cases have been reported in the oral cavity. The authors present the second case located in the floor of the mouth. The treatment of the lesion consists of a local excision.

Spindle cell lipoma in an intramuscular lipoma

Intramuscular lipoma (IML) is a relatively common variant of lipomas. The most important sites for IML are the large muscles of the extremities. Spindle cell lipoma (SCL) is a rare and distinct variant of lipoma. Most SCL arise in the neck, shoulders or back. It has also been described in unusual sites, such as the oral cavity, larynx, bronchus, breast, orbit and extremities. However, localization of a SCL in an IML has not been described yet. Thus, we present the first SCL located in an IML, which was localized underneath the fascia and embedded within the left sartorius muscle of a 55-year-old man. Microscopically, the SCL component of the tumor was sharply circumscribed by a fibrous capsule and clearly separated from the IML in which it was localized. The collagen-forming spindle cells of the SCL showed neither atypia nor pleomorphism. These cells stained positive for CD34, while the mature fat tissue component of the SCL was positive for S-100 protein and negative for CD34. Spindle cells were negative for S-100 protein. Vimentin stained both components of the SCL, as well as the striated muscle fibers and mature fat tissue of the IML. In conclusion, careful morphological observation along with immunohistochemistry for CD34 and S-100 protein are essential to differentiate this rare tumor from lesions that enter the differential diagnosis.

Spindle cell lipoma of the knee: a case report

A rare case of spindle cell lipoma of the knee in a 58-year-old woman is presented. A soft tissue mass on the lateral aspect of the knee, measuring 5 x 6 cm in size, that had been noticed 1 year previously showed slightly lower signal intensities both on T1- and T2-weighted magnetic resonance images than those of subcutaneous adipose tissue. Because pathological findings of the tiny specimen obtained by needle biopsy showed lipogenic tumor and the possibility of well-differentiated liposarcoma could not be ruled out, wide excision was performed. Histopathological examination revealed that the tumor consisted of spindle cells, collagen fibers, and lipocytes. In addition, immunohistochemical study showed positive staining for CD34. From these histological findings, diagnosis of spindle cell lipoma was made. Although expected sites of spindle cell lipoma are the posterior neck, shoulder region, and upper back, it may also arise in the lower extremity. Therefore, when radiological findings suggest lipogenic tumor but are different from those of lipoma, spindle cell lipoma as well as well-differentiated liposarcoma should be considered for differential diagnoses.