Radiological, histopathological, and immunohistochemical characterization of solitary fibrous tumor of the lacrimal sac: A rare case report

Prakash Kumar; Sanjeev Kumar; Rashmi Chandra; Rajendra Kumar

doi:10.4103/jcor.jcor_38_20

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Year : 2021 | Volume : 9 | Issue : 1 | Page : 38-41

Radiological, histopathological, and immunohistochemical characterization of solitary fibrous tumor of the lacrimal sac: A rare case report

Prakash Kumar¹, Sanjeev Kumar², Rashmi Chandra³, Rajendra Kumar⁴
¹ Department of Ophthalmology, Narayan Medical College and Hospital, Sasaram, Bihar, India
² Department of Ophthalmology, Sri Krishna Medical College and Hospital, Muzaffarpur, Bihar, India
³ Department of Ophthalmology, Indira Gandhi Institute of Medical Science, Patna, Bihar, India
⁴ Department of Pathology, Narayan Medical College and Hospital, Sasaram, Bihar, India

Date of Submission	29-Apr-2020
Date of Decision	21-Aug-2020
Date of Acceptance	18-Nov-2020
Date of Web Publication	10-Apr-2021

Correspondence Address:
Sanjeev Kumar
Finance Colony, Phase-2, Khajpura, Patna - 800 014, Bihar
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jcor.jcor_38_20

Abstract

Solitary fibrous tumor (SFT) is a benign spindle cell neoplasm of mesenchymal fibroblast cells. It can appear in various locations, but SFT of the lacrimal sac is rare. Due to their variable clinical, histological, and radiological presentation, it can be easily misdiagnosed. We report a rare case of SFT of the lacrimal sac with its radiological, histological, and immunochemical characterization.

Keywords: Dacryocystectomy, lacrimal sac tumor, solitary fibrous tumor

How to cite this article:
Kumar P, Kumar S, Chandra R, Kumar R. Radiological, histopathological, and immunohistochemical characterization of solitary fibrous tumor of the lacrimal sac: A rare case report. J Clin Ophthalmol Res 2021;9:38-41

How to cite this URL:
Kumar P, Kumar S, Chandra R, Kumar R. Radiological, histopathological, and immunohistochemical characterization of solitary fibrous tumor of the lacrimal sac: A rare case report. J Clin Ophthalmol Res [serial online] 2021 [cited 2022 Jun 27];9:38-41. Available from: https://www.jcor.in/text.asp?2021/9/1/38/313474

Solitary fibrous tumor (SFT) is a spindle cell neoplasm of mesenchymal fibroblastic cells. SFT was first reported by Klemperer and Coleman^[1] in 1931 as “localized mesothelioma” of pleura and mediastinum. This tumor has been reported in numerous other locations and besides the most common origin from pleura and peritoneum. There has been an increasing incidence of the tumor to be found in the extrapleural, extraserosal sites such as lung, liver, breast, meninges, orbit, tracts, deep cervical spaces, skin, kidney, and other organs.^{[2],[3],[4],[5],[6],[7]} It may be misdiagnosed because of variable clinical presentations and histological appearance.

SFT of the orbit may typically present as a benign orbital mass. It may present as unilateral, painless, slowly progressive proptosis or a palpable mass in the periocular area. We present a very rare case of SFT of the lacrimal sac. Worldwide, very few cases of SFT have been reported.

Case Report

A 34-year-old young female presented to our outpatient department with a complaint of excessive lacrimation in her left eye for 3 years associated with a slow-growing mass in the lacrimal sac area [Figure 1]. There was no history of any episode of dacryocystitis. She was using on and off systemic and topical antibiotics for her ocular complaints. Her medical history was unremarkable. On ocular examination, her visual acuity was 20/20 in each eye. The right eye and other ocular findings were normal. On examination of the mass, it was located below the medial canthal tendon and clinically mimicking lacrimal sac mucocele. The size was 1.5 cm × 1.0 cm and its surface was smooth and consistency was firm. Epiphora was recorded in her left eye. No discharge was noted on pressing over the lacrimal sac area. On syringing of lacrimal passages, regurgitation through opposite puncta after a few minutes was noted, but on pressure syringing, there was flow. The syringing findings were suggestive of partial nasolacrimal duct obstruction.

Figure 1: External photograph of the patient showing left eye lacrimal sac tumor

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To differentiate between mucocele and a lacrimal sac tumor, we decided to undergo the radiological evaluation of the lacrimal sac mass by contrast-enhanced computed tomography (CECT) of the orbit and paranasal sinus. On CECT scan, there was evidence of well-circumscribed approximately 2.0 cm × 1.5 cm × 1.8 cm enhancing lesion seen that is centered at the lacrimal fossa which is extending along the medial orbital wall. The lesion did not show any internal calcification or collection or cystic changes, and the lesion is not involving any orbital muscle and bone. Tumor density on precontrast computed tomography (CT) scan was isodense. On postcontrast, CT tumor density was heterogeneous with marked degree of enhancement pattern. CT also showed smooth expansion of the proximal nasolacrimal duct [Figure 2].

Figure 2: Contrast-enhanced computerized tomography of the orbit and paranasal sinus: Axial scan showing a well-circumscribed soft-tissue enhancing lesion in the lacrimal fossa. Smooth expansion of proximal nasolacrimal duct is evident

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Radiological investigation confirms that a mass was arising from the lacrimal sac. On the basis of clinical and radiological finding suggestive of lacrimal sac tumor, we decided to undergo complete surgical removal of mass by dacryocystectomy. After surgical excision with margin clearance, the mass was sent for histopathology.

On gross pathological examination, a well-circumscribed brownish-red mass with high vascularity of the tumor, measuring 2.5 cm × 2.0 cm × 1.5 cm, having firm consistency was found. On cut section, the mass shows a solid brown surface with area of hemorrhage.

Histopathological examination showed oval to spindle cells with high cellularity, and these cells were arranged in staghorn and fascicular pattern. These cells are arranged around the compressed vessels. Area of hemorrhage and 1–2 mitotic figures per high-power field are noted. On the basis of histomorphology, a spindle cell-containing lesion was found [Figure 4] and [Figure 5]. Further immunohistochemistry (IHC) was advised for the characterization of tumor.

Figure 3: Intraoperative photograph showing lacrimal sac tumor

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Figure 4: Histopathology of lacrimal sac tumor section (H and E stain, ×100) showing islands of fibrous tissue proliferation and collagen material

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Figure 5: Lacrimal sac tumor section (H and E stain, ×400) showing prominent vasculature with pericytomatous arrangement of tumor cells without cellular atypia

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As the spindle cell in orbit can have many differential diagnosis as schwannoma, rhabdomyoma, undifferentiated spindle cell carcinoma, and vascular tumor. To rule out the above differential diagnosis, various IHCs were done on the paraffin-embedded section by DAB method and these IHCs include CD-34, CD-99, vimentin, S-100 protein, desmin, and keratin. To know the behavior of tumor whether it is benign or aggressive behavior proliferating index K 1–67 was done, which came on an average 3.5%, indicates benign nature of tumor.

IHC of tumor cell was positive for CD-34, CD-99, and vimentin and negative for S-100 protein, desmin, and keratin, suggesting the possible diagnosis of SFT [Figure 6] and [Figure 7]. Vimentin was strongly expressed by tumor cells. CD-99 was expressed by most of the tumor cells. CD34 was expressed by compressed blood vessels and few tumor cells. K-67 index was 3%–5% (average).

Figure 6: Immunohistochemistry of lacrimal sac tumor showing strongly positive CD-34 cells

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Figure 7: Immunohistochemistry of lacrimal sac tumor showing positive B-cell lymphoma 2

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IHC favors SFT. According to the recent WHO classification 2016 (WHO revised 4^th ed.ition of tumor), hemangiopericytoma is classified in SFT.

Up to 6 months of follow-up visit, there was no recurrence of the mass.

Discussion

There is variability in the radiological appearance of SFT in CT scan and magnetic resonance imaging (MRI), so definitive diagnosis can be made by histopathological and immunohistochemical examination only. On CT scan, SFT generally appears as a well-defined soft-tissue mass. On postcontrast CT and MR images, a heterogeneous and marked pattern of enhancement was found. Although not pathognomonic, homogeneous- or heterogeneous-attenuated enhancement is reported to be the most prominent feature of SFT revealed with CT and MRI imaging, which is attributed to high vascularity because of the prominent vascular channels within the tumor.^{[5],[8],[9],[10]}

SFT shares a common histopathologic morphology with hemangiopericytomas, giant cell angiofibromas, and fibrous histiocytomas, so one school of thought is to classifying all these tumors together under general term SFT. All of these tumors are characterized by haphazardly arranged fibroblast-like cells, indistinct nucleoli, prominent vasculature with perivascular fibrosis, and variable stromal collagen. On microscopic examination, SFT is a well-circumscribed nonencapsulated tumor that shows a patternless arrangement of alternating hypercellular and hypocellular regions of spindle cells against a collagenous background of variable vascularity.

SFT displays a typical pattern of immunohistochemical staining. These tumors stain strongly and diffusely with vimentin, B-cell lymphoma-2 (Bcl-2), and CD-34 and stain negatively for keratin, cytokeratin, epithelial membrane antigen, S100, smooth muscle actin, and desmin. The peculiar immunohistochemical staining pattern helps to differentiate SFTs from neural tumors, smooth muscle tumors, nodular fasciitis, and fibrous histiocytoma. Distinguishing SFTs from hemangiopericytoma can be difficult since they can have the same light microscopic appearance and both stain immunohistochemically for vimentin, BCL-2, and CD-34. The differentiating point is the diffuse and strong immunochemical staining with CD-34, the hematopoietic progenitor cell antigen, which distinguishes SFT from hemangiopericytoma which has weak and patchy CD-34 staining.

Due to its rarity and variability in presentation, there is a high chance of misdiagnosis. Hence, comprehensive ophthalmic examination including radiological, histological, and if needed immunohistochemical investigation should be done to clinch the diagnosis. As there is a high chance of recurrence, complete surgical excision and continued follow-up should be emphasized.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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