Giant Lipoleiomyoma of Cervix Mimicking as Schwannoma: First Case Report of a Dual Morphologic Variant

ABSTRACT

Leiomyomas with schwannoma-like features are very rare and can resemble peripheral nerve sheath tumors, particularly if the characteristics of Verocay bodies and nuclear palisading are present. Inclusion of mature adipose tissue (lipomatous differentiation) within similar tumors is uncommon. To our knowledge, no case with cervical leiomyoma that simultaneously presents schwannoma-like and lipomatous differentiation has been reported. A 54-year-old perimenopausal woman was operated upon for assumed fibroid uterus with total abdominal hysterectomy and bilateral salpingo-oophorectomy. Grossly, the specimen had a giant (20 cm), well-circumscribed cervical mass with bosselated surface. The cut surface was firm, grey-white with focal yellowish spots. Histology revealed a spindle cell tumor with striking nuclear palisading and Verocay body-type features, intermixed with mature adipose tissue. At first, these features were suggestive of schwannoma; however, immunohistochemistry exhibited diffuse smooth muscle actin (SMA) and desmin positivity, with S100 negativity, outlining smooth muscle lineage and categorically excluding neural origin. Lack of atypia, necrosis, or anaplastic cell proliferation further consolidated the diagnosis as benign. This represents the first documented case of a benign cervical leiomyoma exhibiting this dual morphologic pattern, underscoring the importance of recognizing such rare variants to avoid misdiagnosis.

INTRODUCTION

Uterine leiomyomas are the most common mesenchymal neoplasms of the female genital tract, typically composed of uniform spindle cells arranged in interlacing fascicles.[1] Several histologic variants–such as cellular, myxoid, epithelioid, and lipoleiomyomas–are well recognized.[2] However, the presence of schwannian morphology in a leiomyoma is exceedingly rare and may closely mimic peripheral nerve sheath tumors, particularly when features such as nuclear palisading and Verocay body-like structures are extensively observed. In such cases, a thorough histopathological evaluation supplemented by immunohistochemistry (IHC) is essential for establishing an accurate diagnosis. Notably, the coexistence of schwannian and lipomatous differentiation simultaneously in cervical leiomyoma has not been previously reported. We describe a unique case of a patient with multiple giant cervical leiomyomas exhibiting this rare and dual morphologic pattern.

CASE REPORT

The patient is a 54-year-old perimenopausal female presenting with gradual abdominal distension and abnormal uterine bleeding. Clinical and radiological assessment demonstrated an enlarged uterus with multiple leiomyomas. Total abdominal hysterectomy with bilateral salpingectomy was performed on the patient.

Grossly, the surgical specimen included the uterus with bilateral adnexa, along with a significantly enlarged, multiple well-defined cervical tumors. The tumors were almost entirely originating from the cervix and displacing the normal cervical shape [Figure 1]. The maximum size was 13 cm × 12 cm × 12 cm, with a bosselated outer surface. The serosal surface was smooth overall, with focal congestion and hemorrhagic discoloration. The cut surface demonstrated a firm, whorled, grey-white appearance, with interspersed yellowish areas. There was no evidence of necrosis or cystic degeneration. The tumor masses were confined to the cervix without gross infiltration of the adjacent structures as the endometrial cavity seemed unremarkable, and bilateral fallopian tubes appeared grossly normal.

Figure 1.

Gross photograph of the hysterectomy specimen showing a giant, bosselated cervical mass (~13 cm)

Microscopically, the tumors consisted of spindle cells that arranged in intersecting fascicles. There were several discrete foci of mature adipose tissue scattered within the tumor [Figure 2]. In addition, the fascicular pattern was interrupted in several areas by areas with nuclear palisading and alternate hypocellular area suggestive of Verocay bodies. These characteristics gave an impression of the possibility of schwannoma [Figure 3]. There was neither cytologic atypia, coagulative tumor necrosis, nor increased mitosis on rigorous sampling.

Figure 2.

Photomicrograph showing a spindle cell lesion with interspersed mature adipose tissue and hypocellular areas, suggestive of lipomatous and schwannoma-like differentiation (H and E, ×20)

Figure 3.

High-power photomicrograph showing prominent nuclear palisading with intervening acellular zones, characteristic of Verocay body-like structures (H and E, ×40)

Immunohistochemical staining showed diffuse staining with desmin and smooth muscle actin (SMA), which authenticated the smooth muscle lineage of the tumors [Figure 4]. The tumors did not stain with S100, which ruled out its neural origin. The proliferation index with the help of Ki-67 was low, below 5%. These results confirmed the diagnosis of benign cervical leiomyoma with schwannian and lipomatous differentiation.

Figure 4.

Immunohistochemical staining for smooth muscle actin showing strong diffuse cytoplasmic positivity in tumor cells, confirming smooth muscle differentiation (IHC, x40)

DISCUSSION

Leiomyomas are the most frequent uterine mesenchymal neoplasms, frequently encountered in women during the perimenopausal years. They are characteristically histologically represented by interlacing fascicles of spindle cells with eosinophilic and cigar-shaped nucleated cells.[1] There is considerable variability seen in the form of cellular, myxoid, epithelioid, lipoleiomyoma, and atypical types of leiomyomas.[2] However, schwannian differentiation with features of nuclear palisading and Verocay body is an exceedingly rare occurrence in cervical leiomyoma.

The presence of Verocay bodies in the current case led to the consideration of schwannoma in the differential diagnosis. Although schwannian features have been occasionally reported in the setting of uterine smooth muscle tumors, the literature contains fewer than five documented cases.[3,4,5] Yorita et al. documented a uterine leiomyoma with massive schwannoma-like features and infarct type necrosis.[3] Morales et al. reported a giant cervical schwannoma-like leiomyoma that was misdiagnosed as a retroperitoneal tumor.[4] Gisser and Young first demonstrated that while some uterine leiomyomas may exhibit nuclear palisading, akin to schwannomas, ultrastructural studies verified the lack of schwannian features, thereby reaffirming their smooth muscle origin.[5]

Notably, genuine uterine schwannomas–although very rare–have been documented, almost exclusively in the cervix. Around 15 such examples, both benign and malignant, have been documented, thereby attesting that peripheral nerve sheath tumors indeed emerge in the uterus.[6] True schwannomas, in these, S100 positivity is always present. Here, the tumor did not express S100, and instead demonstrated diffuse staining for desmin and SMA, thereby confirming its smooth muscle derivation and ruling out schwannoma definitively.

Notably, schwannoma-like morphology in leiomyomas is more common in gastrointestinal smooth muscle neoplasms, for example, esophageal and intestinal leiomyomas, compared with uterine ones.[7] This renders its occurrence in an uterine tumor highly exceptional. In addition, the simultaneous occurrence of mature adipose tissue, which is characteristic of lipoleiomyomatous differentiation, is uncommon too. Lipoleiomyomas are rare entities, primarily seen in postmenopausal females, and are considered to result from fatty metaplasia during tumor evolution.[8] However, we could not find any reported case with the simultaneous occurrence of schwannoma-like areas and mature adipose tissue within the confines of cervical leiomyoma, to the best of our knowledge.

The other significant consideration was the question of malignancy, especially considering the large size (13 cm × 12 cm × 12 cm) of the tumor. Uterine leiomyosarcoma is still the relevant differential diagnosis with any large uterine tumor. However, absent coagulative tumor necrosis, cytologic atypia, and mitosis–along with sparse Ki-67 labeling–spoke highly in favor of a benign smooth muscle tumor.

In addition, fumarate hydratase-deficient leiomyomas may sometimes show vague nuclear palisading.[9] However, there was no relevant family history, nor any clinical or radiological findings suggestive of hereditary leiomyomatosis and renal cell carcinoma syndrome in our patient. Although fumarate hydratase IHC or molecular testing was not performed, the absence of characteristic histomorphologic features and lack of syndromic context made fumarate hydratase-deficiency unlikely in this case.

CONCLUSION

We report the first known case of a cervical leiomyoma exhibiting both schwannoma-like and lipomatous differentiation–an exceptionally rare histologic combination. The morphology closely mimicked a neural tumor, underscoring the diagnostic challenge. While true cervical schwannomas are known, this case highlights that histology alone may be deceptive, and IHC is essential to establish the correct diagnosis. This case not only expands the histologic spectrum of leiomyomas but also emphasizes the critical role of IHC in distinguishing mimics and avoiding diagnostic pitfalls.

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.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.