Benign fibrous histiocytoma of the lacrimal sac

INTRODUCTION

Fibrous histiocytoma (FH) is a common primary benign tumor of mesenchymal origin. This benign tumor is often seen to appear in areas exposed to the sun, namely, skin, orbital tissues, lids, conjunctiva, and ocular are limbus.^[1,2] The presence of these subcutaneous tumors in deep soft tissues is rare.^[3] Most FH are benign; however, some are locally aggressive and malignant in nature.^[1,2] Unlike the cutaneous form, which is common, non-cutaneous benign FH (BFH) comprises 1% of all BFH lesions. This tumor is commonly seen in the middle-aged; mean age of presentation is 55 years, ranges from 1 to 71 years, commoner in males with a male-to-female ratio of 2.5:1.^[3-5]

A histiocyte or fibroblast is the probable site of origin. It possibly is a primitive mesenchymal cell which has diverge differentiation ability, and can express histiocytic, fibroblastic, and myofibroblastic phenotypes.^[1-6]

BFH frequently originates as a painless mass with non-specific symptoms which result from disruption of normal anatomy and physiology of the region of origin.^[7] These tumors are seen clinically to appear as slowly enlarging, well-circumscribed mass.^[8]

The treatment of this tumor typically involves a wide-margin surgical excision where the complete capsule is removed during excision to avoid recurrence.^[9] Other treatment modalities that have been tried on an individual basis are adjuvant radio or chemotherapy.^[10]

We report a 60-year-old female who came with a three-year history of painless left medial lower lid mass that was excised once, with associated recurrent mucoid discharge and tearing.

CASE REPORT

A 60-year-old Nigerian woman reported with a three-year history of gradual painless swelling involving with the medial aspect of the left lower lid, which was painless, initially small as the size of a black-eyed bean, but progressed slowly to the size of a small peewee egg to erode the overlying skin [Figure 1]. There was an associated history of discharge, tearing from the eye but no bleeding. There was reduced, vision in the left eye, no protrusion of the eye or abnormal deviation of the eye, no previous history of irradiation involving the face or any other part of the body, and no swelling involving other parts of the body. She had an attempted excision done by a traditionalist, and the swelling recurred three months later.

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Figure 1:

Left medial infraorbital mass around the lacrimal sac area with sloughing surface.

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Investigations

The patient had a computed tomography (CT)-scan done, which showed a large exophytic soft-tissue mass arising from the inferomedial pre-septal part of the left orbit. The lesion measured 44 mm × 22 mm × 26 mm and showed homogeneous post-contrast enhancement. There was no demonstrable infiltration of the globe or adjacent medial rectus muscle. The optic nerve, other rectus muscles, and intraocular structures were essentially normal. There was no bony erosion of the adjacent ethmoids, no intracranial extension, and paranasal sinuses were essentially normal. A radiological diagnosis of orbital lymphoma was made [Figure 2].

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Figure 2:

Axial computed tomography scan showing a large exophytic mass without bony erosion.

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Intraoperative findings

Surgery was done under general anesthesia after obtaining informed consent from the patient and on the anesthetist’s confirmation of the patient being fit to undergo the surgical procedure. A curvilinear incision was made 6 mm below the lower lid margin and extended medially and laterally over the cutaneous surface of the mass. A blunt dissection was made to access the lower border of the mass and all around the mass. It was then removed en block, revealing a well-circumscribed mass measuring 3.7 cm × 1.0 cm and a bare lacrimal fossa. Probing and syringing confirmed the absence of the lacrimal sac. Hemostasis was secured, exposing a dead space, which was closed by suturing in layers with Vicryl 5/0 absorbable suture, followed by firm pressure padding [Figure 3].

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Figure 3:

(a) A dead space seen following the removal of the mass with lacrimal probes exposed on passing them through the superior and inferior punta. (b) A well-circumscribed encapsulated mass measuring 3.7 cm by 1 cm.

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Pathology of the specimen

Gross findings

Excised mass was an encapsulated greyish brown soft to firm mass with a smooth external surface. It was roughly spherical and measured 3 cm in its long diameter and 2 cm in its shorter diameter. Serial cut sections showed a mostly greyish-white homogenous surface with dark brown spots [Figure 4].

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Figure 4:

A resected lower lid mass with greyish-white cut surfaces.

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Microscopy findings

Histologic sections of the lower lid mass showed a scanty eosinophilic hyaline stroma within which was seen monomorphic spindle cells with ill-defined eosinophilic cytoplasm and elongated bland vesicular nuclei disposed in storiform pattern. Multinucleated giant cells, a few staghorn-like blood vessels, and scanty mitotic figures were also noted [Figure 5].

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Figure 5:

(a) Photomicrograph (hematoxylin and eosin) ×100 magnification showing prominent storiform pattern of bland spindles cells. (b) (×400 magnification) showing bland spindle cells with vesicular nuclei in storiform pattern and multinucleate giant cells.

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Post-operative care

The pressure padding was left over the area for 72 hours, and the patient was placed on oral systemic analgesics (Diclofenac 50 mg twice daily for 5 days, oral systemic antibiotic (Augmentin 625 mg twice daily for 7 days), Vitamin C 200 mg 3 times daily for 7 days, and tabs Chymotrypsin 20,000 units orally 3 times daily. The pressure dressing was removed on the fourth day, and the patient was discharged home.

Post-operative follow-up

The patient was seen in the clinic at one week and four weeks after discharge. The wound edge was well apposed and healing well. She still had tearing from her left eye, and she has planned for left cataract extraction after three months of review [Figure 6].

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Figure 6:

Wound at one week postoperative review.

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DISCUSSION

BFH can be classified anatomically into cutaneous and deep forms. The deep FH is rare, accounting for about 1–2% of all BFH.

This is the first documentation of a BFH involving the eyelid and the lacrimal sac in our institution and the north-central part of Nigeria. Fibrous histiocytoma is a rare tumor whose ocular manifestations usually involve the orbit or, less commonly, the ciliary body and conjunctiva. The fibrous histiocytoma involving the lacrimal sac is rare, and very few cases have been reported globally.^[10] The tumor most commonly arises in the dermis but may also arise from parenchymal organs and soft tissues. The BFH is often seen to appear in areas exposed to sun, namely, skin and orbital tissues, while the presence of this tumor in the deeper soft tissue of the head and neck has been rarely reported.^[2] The tumor has been reported to have a slight male predilection by some authors;^[2] however, we present this in a female.

Subcutaneous BFH is mostly painless masses that are nodular, with minimal mobility and firm to elastic in consistency, mostly without bony erosion. For BFH, mostly the skin overlying the lesion is normal with no lymphadenopathy. Clinically, the tumor appears as a soft-tissue lesion.^[3] Deep BFH commonly appears as a painless, slow-growing mass whose symptoms are manifested by the disruption of normal anatomy and physiology of the body part where the tumor originates.^[2]

Orbital radiological imaging such as CT, magnetic resonance imaging, and/or time-resolved contrast kinetics imaging has a significant role in the accurate diagnosis of this lesion; they usually reveal a well-circumscribed soft-tissue mass. It can resemble a cavernous hemangioma or a schwannoma. A biopsy with special immunohistochemistry staining is necessary to arrive at a definitive diagnosis.^[1]

The preferred management of benign fibrohystiocytoma is complete surgical excision of the mass with its capsule. The literature review has shown that incomplete excision is a cause of disease recurrence and can also cause malignant transformation. Advanced cases may require orbital exenteration or irradiation.^[1] The rate of recurrence has been reported to be up to 31%.

CONCLUSION

Benign FH involving the lacrimal sac is of rare occurrence. Imaging modalities and histopathology can clinch the diagnosis. Complete excision of the tumor, including its capsule, is the definitive treatment for this condition.