Surreal illustration of an eye symbolizing Conjunctival Leiomyosarcoma, a rare eye tumor.

Conjunctival Leiomyosarcoma: Understanding This Rare Eye Tumor

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Beau Callahan in Health & Wellness December 2025 • 4 min read.

"A deep dive into a unique case of conjunctival leiomyosarcoma, its diagnosis, and what it means for those affected."


Leiomyosarcomas, cancers arising from smooth muscle tissue, are relatively common, but their occurrence in the eye is exceptionally rare. This article explores the specifics of conjunctival leiomyosarcoma, focusing on a recent case study to shed light on its diagnosis and management.

We'll delve into the histopathological features of a patient diagnosed with this unusual tumor. The patient, a 38-year-old HIV-positive male, presented with redness in his right eye and a noticeable mass on the conjunctiva. Despite the initial clinical assessment suggesting a different type of cancer, the final diagnosis revealed a leiomyosarcoma.

This exploration aims to provide a comprehensive understanding of conjunctival leiomyosarcoma. We will cover the clinical history, diagnostic process, and the critical role of accurate identification to avoid misdiagnosis in such uncommon presentations.

Unpacking the Diagnosis: What to Know About Conjunctival Leiomyosarcoma

Surreal illustration of an eye symbolizing Conjunctival Leiomyosarcoma, a rare eye tumor.

The patient, a 38-year-old HIV-positive male not undergoing antiretroviral treatment, sought medical attention for a mass on his right conjunctiva. Besides the eye issue, the patient was in good health without any other noticeable soft tissue masses. An ophthalmic examination revealed hyperaemia in the right eye, along with a raised lesion on the medial aspect of the conjunctiva, extending towards the cornea. His vision was unimpaired. The initial clinical assessment pointed towards an invasive squamous cell carcinoma.

The patient underwent a monoblock excision of the mass followed by cryotherapy to the base, with clinical margins appearing clear of the tumor. The excised tissue was then sent for histopathological evaluation, but the patient did not return for follow-up, limiting long-term tracking of the case.

  • Microscopic Examination: A single tissue fragment showed intact squamous mucosa with mild dysplasia at one edge. A spindle cell proliferation was noted within the underlying tissue.
  • Cell Morphology: Fascicles of spindle cells with varying degrees of atypia were observed. The cells were large and hyperchromatic; some contained perinuclear vacuoles. Mitotic activity was evident, with up to 14 mitotic figures per 10 high-powered fields.
  • Immunohistochemistry: Cytokeratin and p63 stains were negative, ruling out spindle cell carcinoma. Melanocytic markers (S100, MiTF, Melan-A, and HMB-45) were also negative, excluding melanoma. Kaposi sarcoma was excluded with negative staining.
  • Positive Markers: Desmin, smooth muscle actin (SMA), muscle-specific actin (MSA), and h-Caldesmon stains were positive in tumor cells. Myogenin and Myo-D1 stains were negative, excluding rhabdomyosarcoma. Epstein-Barr encoding region (EBER) in-situ hybridization was negative.
The final diagnosis was conjunctival leiomyosarcoma. Leiomyosarcomas are malignant smooth muscle tumors typically found in soft tissues, particularly in the retroperitoneal area. Ocular occurrences are rare, with only a few reported cases. These tumors consist of spindle cells arranged in fascicles, characterized by cigar-shaped nuclei with variable pleomorphism and eosinophilic cytoplasm. Mitotic activity is common, and immunohistochemistry typically shows positivity for SMA, MSA, desmin, and h-Caldesmon. The size and location of such tumors are critical prognostic indicators, with potential for local recurrence or distant metastasis.

Key Takeaways: Why Early and Accurate Diagnosis Matters

Conjunctival leiomyosarcoma, though rare, should be considered in the differential diagnosis of conjunctival spindle cell neoplasms. While spindle cell carcinoma is often the primary suspect, excluding other possibilities like primary sarcomas is crucial for accurate diagnosis and appropriate management.

This case underscores the significance of thorough histopathological examination and immunohistochemical analysis in diagnosing unusual tumors. Accurate diagnosis is vital for determining the best treatment strategy and improving patient outcomes.

Increased awareness and vigilance among clinicians are essential for early detection and management of conjunctival leiomyosarcomas. Further research and case studies will enhance our understanding and refine diagnostic and therapeutic approaches for this rare condition.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1177/2050313x17724060, Alternate LINK

Title: Conjunctival Leiomyosarcoma: A Fairly Common Tumour In An Uncommon Site

Subject: General Medicine

Journal: SAGE Open Medical Case Reports

Publisher: SAGE Publications

Authors: Reubina Wadee

Published: 2017-01-01

Everything You Need To Know

1

What exactly is Conjunctival leiomyosarcoma?

Conjunctival leiomyosarcoma is a rare, malignant tumor originating from the smooth muscle in the conjunctiva, the clear membrane covering the white part of the eye and the inner surface of the eyelids. It's characterized by spindle cells arranged in fascicles, with specific histopathological features. Its significance lies in its rarity and the importance of distinguishing it from other, more common, conjunctival tumors.

2

How is Conjunctival leiomyosarcoma typically diagnosed?

The diagnosis of Conjunctival leiomyosarcoma involves several steps. Initial clinical assessment might suggest a different type of cancer, such as an invasive squamous cell carcinoma. However, a monoblock excision of the mass is performed, and the tissue undergoes histopathological evaluation. Microscopic examination, cell morphology assessment, and immunohistochemistry are crucial. Immunohistochemistry uses specific markers like Desmin, smooth muscle actin (SMA), muscle-specific actin (MSA), and h-Caldesmon to confirm the diagnosis by identifying the tumor cells.

3

Why is immunohistochemistry important in diagnosing this condition?

Immunohistochemistry is a vital diagnostic tool in identifying Conjunctival leiomyosarcoma. It employs specific stains and markers to differentiate the tumor from other types of cancer. For example, negative Cytokeratin and p63 stains exclude spindle cell carcinoma, while negative melanocytic markers rule out melanoma. Positive markers like Desmin, SMA, MSA, and h-Caldesmon are indicative of a smooth muscle origin, confirming the diagnosis of leiomyosarcoma. This is essential to avoid misdiagnosis and ensure appropriate treatment.

4

What are the implications of misdiagnosing Conjunctival leiomyosarcoma?

The implications of misdiagnosing Conjunctival leiomyosarcoma are significant. An incorrect diagnosis can lead to inappropriate treatment, potentially worsening the patient's condition. Accurate diagnosis is critical for effective management, which may involve surgical excision, potentially followed by other therapies. Considering the rarity of this tumor, an accurate diagnosis is paramount to improve patient outcomes and prevent unnecessary interventions.

5

Does the patient's HIV status have any bearing on the presentation of Conjunctival leiomyosarcoma?

While not explicitly detailed, the patient's HIV-positive status could potentially influence the clinical presentation or treatment approach for Conjunctival leiomyosarcoma. Patients with compromised immune systems might be more susceptible to certain types of cancer, or their response to treatment could be different. However, the article focuses on the tumor's characteristics and diagnostic process and does not elaborate on the direct impact of the patient's HIV status on the tumor itself, or the treatment.

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