Recurrent dermatofibrosarcoma protuberans involving the lacrimal sac: A case report

Abstract

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a rare, low-grade, locally aggressive cutaneous sarcoma. DFSP in the periocular region is exceedingly rare, leading to diagnostic and surgical challenges due to anatomical constraints in the periocular region. Precise diagnosis is essential to guide appropriate surgical management and prevent recurrence.

CASE SUMMARY

A 32-year-old female presented with a recurrent tumor in the medial canthus, previously diagnosed as a solitary fibrous tumor in an outside institution. After complete radiological and systemic workup, she was scheduled for a wide local excision followed by reconstruction after getting tumor clear margins on frozen section. Histopathology confirmed DFSP, characterized by storiform spindle cell proliferation, diffuse cluster of differentiation 34 positivity, and signal transducer and activator of transcription 6 negativity.

CONCLUSION

This case highlights the challenges in the diagnostic and surgical management of DFSP in periocular tumors. Comprehensive surgical excision with appropriate reconstruction is critical for achieving oncological control while preserving aesthetics and function.

Key Words: Dermatofibrosarcoma protuberans; Medial canthus tumor; Solitary fibrous tumor; Wide local excision; Cluster of differentiation 34; Signal transducer and activator of transcription 6; Case report

Core Tip: Periocular dermatofibrosarcoma protuberans (DFSP) of the lacrimal sac is extremely rare, often mimicking benign or inflammatory lesions, leading to delayed diagnosis. High clinical suspicion is warranted for slowly enlarging, firm, painless medial canthal masses. Histopathology with cluster of differentiation 34 immunopositivity confirms the diagnosis. Complete surgical excision with histologically clear margins is crucial to prevent recurrence, with consideration for Mohs micrographic surgery in select cases. Long-term follow-up is essential due to the locally aggressive nature of DFSP and potential for late recurrence. Early recognition and meticulous margin control are key to optimal functional and cosmetic outcomes.

INTRODUCTION

Dermatofibrosarcoma protuberans (DFSP) is a rare, slow-growing, cutaneous soft tissue sarcoma of fibroblastic origin, representing less than 0.1% of all malignancies and approximately 1%-6% of all soft tissue sarcomas[1,2]. It predominantly affects young to middle-aged adults and shows a predilection for the trunk (50%-60%) and proximal extremities (20%-30%)[3]. Head and neck involvement accounts for 10%-15% of cases, but periocular DFSP, particularly involving the lacrimal sac or medial canthus, is exceedingly rare and sparsely documented in the literature[4,5].

Histologically, DFSP is characterized by a monotonous proliferation of spindle cells arranged in a storiform or cartwheel pattern, infiltrating the dermis and subcutaneous tissue[1,6]. The differential diagnosis includes a spectrum of benign and malignant spindle cell tumors, particularly solitary fibrous tumor (SFT), which shares overlapping morphological features. Both DFSP and SFT are cluster of differentiation 34 (CD34)-positive spindle cell neoplasms; however, SFT is distinguished by the nuclear expression of signal transducer and activator of transcription 6 (STAT6) resulting from the NGFI-A binding protein 2 (NAB2)-STAT6 fusion gene[7,8]. By contrast, DFSP harbors a specific chromosomal translocation t(17;22)(q22;q13) leading to the collagen type 1 alpha 1-platelet-derived growth factor beta gene fusion, which drives autocrine platelet-derived growth factor receptor beta activation[9,10].

Accurate diagnosis is critical as DFSP is locally aggressive and demonstrates a high propensity for local recurrence if not adequately excised, with recurrence rates ranging from 10% to 60% following standard wide local excision[11]. Mohs micrographic surgery has been advocated as the gold standard, particularly in functionally and cosmetically sensitive areas like the face and periocular region, due to its superior margin control and lower recurrence rate (0%-6.6%)[12].

Management of DFSP in the periocular region poses unique surgical challenges due to the proximity to critical anatomical structures such as the medial canthal tendon, lacrimal drainage system, and orbital contents. Achieving oncologic clearance while preserving ocular function and aesthetic integrity requires interdisciplinary collaboration and meticulous reconstructive planning[13]. This case report presents a rare instance of recurrent DFSP involving the lacrimal sac and medial canthus, initially misdiagnosed as SFT. The diagnostic pitfalls, surgical strategy involving wide local excision and Mustarde flap reconstruction, and the role of immunohistochemistry in definitive diagnosis are discussed, with a review of the current literature.

CASE PRESENTATION

Chief complaints

A 32-year-old female presented with a recurrent swelling located inferior to the right medial canthus, which she had first noticed in 2017 as a painless, slowly enlarging nodular lesion (Figure 1A).

Figure 1 A case of recurrent dermatofibrosarcoma of lacrimal sac in a young female. A: Clinical photo showing a medial canthal soft tissue mass extending to the nasolacrimal duct; B: Contrast-enhanced computed tomography of the face demonstrated a well-defined soft tissue mass extending from the medial canthus to the nasolacrimal duct, with canal dilation but no bony erosion or orbital extension; C: Intraoperative photo after tumor excision showing the grossly enlarged nasolacrimal canal (marked in yellow arrow); D: Clinical photo taken after 2 years of follow-up showing a depressed scar with acceptable cosmesis without any recurrence.

History of present illness

The growing mass prompted the patient to seek further evaluation due to increasing cosmetic disfigurement, although she reported no associated symptoms such as pain, ulceration, bleeding, diplopia, or visual impairment.

History of past illness

Seven years prior, she underwent surgical excision at a local healthcare facility. Histopathological examination at that time suggested a diagnosis of SFT, although no immunohistochemical or molecular studies were performed to confirm the diagnosis. Two years following the initial surgery, the lesion recurred and demonstrated progressive enlargement over the subsequent 4 years, eventually reaching a size of approximately 5 cm × 4 cm. Her past medical history was unremarkable, with no known systemic comorbidities.

Personal and family history

She had no relevant family history of soft tissue tumors.

Physical examination

On clinical examination, the patient had a best-corrected visual acuity of 20/20 in both eyes. The lesion measured approximately 5 cm × 4 cm, was soft, non-tender, non-compressible, and did not transilluminate. The overlying skin showed patchy hypopigmentation. There were no signs of orbital invasion, palpable lymphadenopathy, or other local complications.

Laboratory examinations

Her blood investigations of complete blood count, erythrocyte sedimentation rate, coagulation profile, blood sugar, liver function tests, and renal function tests were within normal limits. Histopathological examination: The wide local excision specimen measured 3.9 cm × 3.5 cm × 3.0 cm and included an overlying skin flap. On gross examination, the cut surface appeared homogenous, gray-white, and solid, with no areas of necrosis or hemorrhage. Microscopic analysis revealed a storiform arrangement of spindle cells with moderate eosinophilic cytoplasm, elongated nuclei, fine chromatin, and mild nuclear atypia, but no mitotic figures were detected (Figure 2A). The tumor infiltrated into the subcutaneous fat and was associated with hyalinized blood vessels, perivascular multinucleated giant cells, and interspersed mast cells. Immunohistochemical staining demonstrated strong, diffuse membranous positivity for CD34, while nuclear staining for STAT6 was negative (Figure 2B). The tumor was excised with clear margins, measured as follows: Anterior/skin: 0.2 cm, posterior: 0.1 cm, superior: 0.5 cm, inferior: 0.5 cm, lateral: 0.7 cm, and medial: 0.2 cm.

Figure 2 Histopathological characteristics of the excised specimen confirming the diagnosis of dermatofibrosarcoma protruberans. A: Histopathology hematoxylin and eosin staining, 400 ×. The tumor is composed of spindle cells arranged in a storiform pattern. The cells showed elongated nuclei, abundant fibrillar cytoplasm, and mild nuclear atypia; B: Immunohistochemistry showed that the tumor cells have strong and diffuse positivity for cluster of differentiation 34.

Imaging examinations

Contrast-enhanced computed tomography of the face demonstrated a well-defined soft tissue mass extending from the medial canthus to the nasolacrimal duct, with canal dilation but no bony erosion or orbital extension. Intense arterial enhancement suggested vascularity from external carotid branches (Figure 1B).

MULTIDISCIPLINARY EXPERT CONSULTATION

Following detailed preoperative evaluation, a multidisciplinary team comprising oculoplastic, maxillofacial, and oncologic surgeons formulated a surgical plan to address the tumor extent and anatomical complexity.

FINAL DIAGNOSIS

After complete clinico-radiological and histopathological examination and multidisciplinary consultation, a final diagnosis of DFSP was made.

TREATMENT

Under general anesthesia, surgical access was achieved using a modified Weber-Ferguson incision with an infraciliary extension to allow optimal exposure. The tumor was excised en bloc with a 2 cm peripheral margin, which included a skin island to ensure oncological clearance. Given the tumor extension along the nasolacrimal duct, curettage of the lacrimal sac mucosa was performed to address potential microscopic invasion. Intraoperatively, a very wide nasolacrimal canal measuring 8 mm in diameter was visualized, which was probably due to the pressure effect of the tumor (Figure 1C). Reconstruction of the resultant defect, measuring in the medial canthal and cheek region, was accomplished using a Mustarde cheek advancement flap mobilized from the nasolabial fold, providing a tension-free and aesthetically favorable closure. A mini-Romovac drain was placed in the surgical cavity to prevent fluid accumulation. Layered wound closure was performed, with deep sutures placed using 3-0 Vicryl to anchor the flap to the periosteum, and interrupted skin sutures using 5-0 Ethilon.

OUTCOME AND FOLLOW-UP

The patient recovered uneventfully and has been under regular follow-up for the last 2 years. She had a good cosmetic and functional outcome without any recurrence (Figure 1D).

DISCUSSION

DFSP is a rare, low-grade dermal sarcoma of fibroblastic origin that exhibits slow but infiltrative growth and a significant propensity for local recurrence if incompletely excised. While the tumor most commonly involves the trunk and proximal extremities, head and neck presentations comprise only 10%-15% of cases, with periocular involvement being exceedingly rare[1-3]. In particular, DFSP involving the lacrimal sac is a diagnostic challenge, with only isolated case reports available in the literature[4,5]. Schittkowski and Wrede[4] reported an orbital presentation of DFSP managed surgically, underscoring the need for early and accurate histological diagnosis in these rare sites. Erickson et al[5] described a similar case masquerading as a lacrimal sac tumor, which required resection and adjuvant radiotherapy. Table 1 describes the clinical manifestations and management of the two rare reported cases of DFSP involving the lacrimal sac[4,5,14,15].

Table 1 Reported cases of isolated dermatofibrosarcoma protuberans involving lacrimal sac and orbit, their clinical manifestations, and their management.

Ref.	Patient demographics	Clinical presentation	Imaging findings	Histopathology & IHC	Treatment	Outcome/follow-up
Erickson et al[5], 2015	71/male	Indolent growth above left medial canthus	CT: 2.1 cm × 2.2 cm × 2.5 cm mass extending into medial orbit and proximal nasolacrimal duct	Spindle cells in storiform pattern; CD34-positive; t(17;22) translocation absent	Surgical excision; partial intensity-modulated radiation therapy	No recurrence at 11 months
Schittkowski and Wrede[4], 2013	45/female	Mild epiphora; palpable mass in lacrimal sac	Not specified	Not specified	Surgical excision	Not specified
Sharma et al[14], 2017	50/female	Swelling in the medial aspect of the right eye associated with pain and diminution of vision	MRI: 5.4 cm × 3.8 cm × 4.1 cm in right orbit with extension to the ethmoid and frontal sinus, similar lesion in left medial canthus	Spindle tumor cells are uniform in appearance, with elongated nuclei, little or no pleomorphism, mitotic figures arranged in a storiform manner, CD34-positive and vimentin-positive	Palliative radiotherapy 20 Gy in five fractions, followed by tab Imatinib 400 mg per day increased to 800 mg per day after 2 years	Stable disease on tablet imatinib 800 mg per day on last follow-up
Rahman et al[15], 2013	70/female	Painless progressive swelling of left eye for 4 years	MRI: Well-defined lobulated soft tissue mass in the superolateral aspect of the left orbit measuring 58 mm × 42 mm × 38 mm, occupying the retro-orbital compartment with expansion of the bony wall and stretching of the optic nerve	Spindle cell tumor composed of slender to plump spindle cells arranged in storiform and focal pericytoma pattern, CD34-positive, S100-negative	Total orbital exenteration of the left eye with split-thickness skin graft from the thigh	No recurrence at 24 months
Present case	32/female	Recurrent swelling inferior to right medial canthus for 6 years	CT: Soft tissue mass extending from medial canthus to nasolacrimal duct, causing canal widening	Storiform spindle cell proliferation; CD34-positive; STAT6-negative	Wide local excision with Mustarde flap reconstruction	No recurrence at 2-year follow-up

CD34: Cluster of differentiation 34; CT: Computed tomography; IHC: Immunohistochemistry; MRI: Magnetic resonance imaging; STAT6: Signal transducer and activator of transcription 6.

Histologically, DFSP is composed of spindle cells arranged in a storiform pattern and infiltrating the dermis and subcutaneous fat. However, these features are shared by other spindle cell neoplasms, particularly SFT, which often leads to diagnostic ambiguity[6,8]. Immunohistochemistry plays a crucial role in resolving this overlap. Both DFSP and SFT are characteristically positive for CD34, but SFT exhibits nuclear expression of STAT6 due to the NAB2-STAT6 gene fusion - a marker absent in DFSP[9,10]. In the present case, the lesion was initially misclassified as SFT due to reliance solely on histomorphology, resulting in delayed definitive management. However, the immunohistochemistry confirmed CD34 positivity and STAT6 negativity, consistent with DFSP. Molecular analysis further enhances diagnostic accuracy. The defining genetic alteration in DFSP is a translocation t(17;22)(q22;q13), leading to fusion of the collagen type 1 alpha 1 and platelet-derived growth factor beta genes, resulting in autocrine activation of platelet-derived growth factor receptor beta signaling[1,7,11]. This molecular signature not only serves as a diagnostic tool but also has therapeutic implications, as it renders DFSP responsive to targeted therapy with imatinib, particularly in advanced or unresectable cases[12]. Management of periocular DFSP is inherently complex due to the proximity of vital structures such as the medial canthal tendon, lacrimal sac, and orbital contents. While Mohs micrographic surgery is considered the gold standard due to superior margin control and lower recurrence rates (0%-6.6%), its availability is limited in many settings[13,16]. Wide local excision with at least 4 cm margins remains a widely accepted alternative, although anatomical constraints in the periocular region often necessitate modification of this principle[1,7]. In this case, oncologic resection with a 2 cm margin was achieved, followed by defect reconstruction using a Mustarde cheek advancement flap. This technique provides well-vascularized tissue and allows tension-free closure while preserving facial symmetry, making it an ideal option for medial canthal and midfacial reconstruction. The success of this reconstructive strategy was evident in the patient’s satisfactory cosmetic outcome and the absence of recurrence over a two-year follow-up. Despite clear surgical margins, DFSP is associated with local recurrence rates ranging from 10% to 60%, with increased risk when margins are narrower than 1 cm or in high-risk histologic variants such as fibrosarcomatous DFSP[8,13]. Our patient’s closest margin was 0.1 cm posteriorly, reflecting the anatomical limitations of the region. The patient didn’t consent to chemotherapy or radiotherapy. Adjuvant radiotherapy is to be considered in the presence of risk factors like close margins, recurrent tumors, aggressive histological subtypes, or in case of positive margins[17]. In a subset of patients with inoperable or metastatic disease, imatinib therapy is warranted following confirmation of translocation t(17;22)(q22;q13). Imatinib is an inhibitor of platelet-derived growth factor receptor beta, ABL, and KIT[18], and blocks platelet-derived growth factor signaling, interfering with phosphorylation of the receptor tyrosine kinase. In borderline resectable cases, neoadjuvant imatinib can be used until a maximum response is documented before proceeding to surgery.

Consequently, long-term surveillance with annual magnetic resonance imaging and patient education for self-monitoring were instituted, with recommended follow-up strategies[7,12]. Overall, this case reinforces the necessity of a multidisciplinary approach involving precise diagnosis using immunohistochemistry and molecular tools, tailored surgical resection, and advanced reconstructive techniques in managing DFSP of the lacrimal sac.

CONCLUSION

This case emphasizes the critical role of immunohistochemistry and molecular diagnostics in evaluating periocular spindle cell tumors. When correctly diagnosed, DFSP can be effectively managed with wide local excision and appropriate reconstructive techniques. Given the high risk of recurrence, long-term surveillance is essential. Interdisciplinary collaboration and awareness of rare presentations are key to achieving favorable outcomes.