Solitary extramedullary plasmacytoma mimicking ocular surface squamous neoplasia in an elderly male: A case report

Abstract

BACKGROUND

Conjunctival plasmacytoma is an exceedingly uncommon form of extramedullary manifestation of multiple myeloma, with only a handful of cases reported so far.

CASE SUMMARY

A 66-year-old male of Indian origin with multiple myeloma presented with a 1-year history of progressive pink mass associated with itching in his left eye. Examination revealed a pinkish conjunctival mass with telangiectasia extending up to the temporal limbus, mimicking ocular surface squamous neoplasia. The patient underwent successful excision of the mass and amniotic membrane grafting. Histopathological examination after excision revealed plasma cell infiltration, confirming an unusual extramedullary manifestation of multiple myeloma. The patient was followed up for one year, with no evidence of recurrence.

CONCLUSION

This case report highlights the importance of considering multiple myeloma in the differential diagnosis of ocular masses, particularly in patients with a known history of the disease. The presentation of a conjunctival mass in a patient with multiple myeloma is rare, but it is essential to recognize this possibility to ensure timely and appropriate management.

Key Words: Conjunctival mass; OSSN; Extramedullary plasmacytoma; Multiple myeloma; Case report

Core Tip: Conjunctival plasmacytoma is a rare extra medullary manifestation of multiple myeloma that can clinically mimic ocular surface squamous neoplasia. This case highlights the importance of including multiple myeloma in the differential diagnosis of atypical conjunctival masses, especially in patients with a known history of the disease, to enable accurate diagnosis and timely intervention.

INTRODUCTION

Multiple myeloma is a hematological malignancy characterized by clonal proliferation of plasma cells in the bone marrow. It accounts for approximately 10% of hematological malignancies[1]. Extramedullary involvement is rare in patients, with newly diagnosed multiple myeloma incidence ranging from 0.5% to 4.8%, while in relapsed and refractory multiple myeloma the reported incidence is 3.4% to 14%[2], and ocular manifestations are even more uncommon, reported cases include conjunctival masses, orbital involvement[3], retinal abnormalities, optic neuropathy and uveitis[4].

CASE PRESENTATION

Chief complaints

A 66-year-old elderly Indian male presented with a pink mass in the conjunctiva of the left eye for one-year duration.

History of present illness

The patient presented with a one-year history of an insidious onset, gradually progressive, painless, pink colour mass in the left eye, associated with intermittent itching.

History of past illness

There was no history of prior ocular surgeries or trauma. He had a history of treatment for multiple myeloma (International Staging System Stage II) diagnosed three years ago and was currently on maintenance therapy with tablet Lenalidomide 10 mg once daily and injection Denosumab 120 mg twice yearly.

Personal and family history

The patient denied any family history of malignancy.

Physical examination

On physical examination, the vital signs were within normal limits. On ocular examination, the best corrected visual acuity in both eyes was 6/9, with a full range of extraocular movement in both eyes. Examination of the left eye revealed a pinkish conjunctival mass extending up to the temporal limbus, with nodularity and telangiectatic vessels of size 5 mm × 4 mm. The mass was painless without any evidence of suppuration or hemorrhage (Figure 1). The right eye examination was found to be within normal limits. Dilated fundoscopy examination of both eyes was within normal limits.

Figure 1  Clinical photo of left eye conjunctival mass size 5 mm × 4 mm extending from limbus with prominent intrinsic vascularity suggestive of ocular surface squamous neoplasia.

Laboratory examinations

At the time of presentation at our clinic, his routine systemic workup for multiple myeloma were above the normal range i.e. Serum kappa-free light chain level was found to be 64.720 mg/L (normal range 3.3-19.4mg/L), Serum lambda free light chain level was 56.890 mg/L (normal range 5.71-26.30mg/L) however the Free Kappa: Lambda ratio 1.138 (normal range 0.26-1.65mg/L) was within normal limit. And Serum Beta 2 Microglobulin level (Nephalometry method) was found to be 3903.99 ng/mL (normal range 800-2340 ng/mL), Complete blood count revealed hemoglobin 12.4 g/dL, white blood counts count of 2.87 × 10⁹/L and RBC count 4.18 × 10¹²/L. Bone Marrow Aspirate showed a bone marrow plasma cell fraction of 3%. The cytogenetic risk profile could not be done due to financial constraints.

Imaging examinations

Fluorodeoxyglucose positron emission tomography computed tomography scan showed no evidence of any lytic lesions or any extraosseous disease at the time of presentation.

MULTIDISCIPLINARY EXPERT CONSULTATION

Mutidisciplinary expert consultation with the pathologist and a medical oncologist was done.

FINAL DIAGNOSIS

A provisional diagnosis of ocular surface squamous neoplasia was made, and the mass was planned for excision under local anesthesia with wide margins (3 mm). The excised mass was sent for frozen section biopsy. Histopathological examination revealed plasma cell infiltration (Figure 2A). Immunohistochemistry showing positive for CD 138, Kappa and Lambda (Figure 2B), thus confirming the diagnosis of conjunctival plasmacytoma.

Figure 2 Histopathological changes of conjunctiva showing. A: Sub conjunctival perivascular aggregates of reactive plasma cells (H&E, 40×); B: Immunohistochemistry (20×) of conjunctival mass showing plasma cells immune-positive for CD138, kappa, and lambda.

TREATMENT

Under local anaesthesia, the conjunctival mass was excised with a wide margin of 3 mm of uninvolved tissue. An absolute alcohol soaked swab was applied over the cornea after marking 3 mm of uninvolved margins, followed by debridement of the corneal epithelium (Kerato-epitheliectomy). The excised mass, along with the debrided corneal epithelium, was sent for frozen section examination. After margin clearance was confirmed on frozen section, a double freeze-thaw cryotherapy was applied slowly over the excised conjunctival and corneal margins. The ocular surface reconstruction was then performed with a wet amniotic membrane graft secured with 8-0 Vicryl suture and eye patching were done.

OUTCOME AND FOLLOW-UP

Postoperatively, he was prescribed topical Moxifloxacin+Dexamethasone, tapered over 1 month, and topical lubricant for 3 months. To prevent any recurrence, prophylactic topical chemotherapy with Mitomycin C was planned. He was prescribed to start freshly prepared topical Mitomycin C (0.04%) four times daily for 2 weeks on and 2 weeks off for three cycles. Tab Lenalidomide was continued as maintenance therapy according to the advice of the medical oncologist. Follow-up at two weeks and 6 months showed no signs of recurrence (Figure 3).

Figure 3 Clinical photo at follow up of two weeks and six months respectively showing. A: Amniotic membrane in place with minimal congestion and sub conjunctival hemorrhage; B: Healed conjunctiva without any recurrence.

DISCUSSION

This case report presents a rare instance of an extramedullary plasmacytoma manifesting as a conjunctival mass in a patient with multiple myeloma. The occurrence of extramedullary plasmacytoma in patients with multiple myeloma is estimated to be approximately 7%-17%[5]. However, conjunctival involvement is exceedingly uncommon, with only a few reported cases in the literature[6-8]. The diagnosis of an extramedullary plasmacytoma was confirmed by histopathological examination, which revealed clonal plasma cell infiltration. Immunohistochemistry staining showed positivity for CD138, CD56, and kappa light chains[9]. Initially, the clinical appearance of the conjunctival mass was suggestive of ocular surface squamous neoplasia (OSSN), which typically presents as a gelatinous or leukoplakic lesion with irregular surfaces and raised edges. It often arises in the interpalpebral zone, with a predilection for the nasal quadrant. The lesions can be papillary, plaque-like, or nodular, and may exhibit a range of colors, including pink, red, or white[10]. OSSN is a common malignancy of the ocular surface, accounting for approximately 4%-29% of all ocular surface tumors[11].

The uniqueness in our patient was that the intraoperative frozen section and histopathological evaluation in our patient revealed a distinct plasma cell infiltrate, prompting a diagnosis of conjunctival plasmacytoma, which was later confirmed with Immunohistocytochemistry. This highlights the importance of intraoperative frozen section in guiding surgical decisions and altering the course of treatment.

Extramedullary plasmacytoma can involve various organs, with the most common sites being the lungs (30%-40%), liver (20%-30%), and kidneys (10%-20%), other less common sites of involvement include the skin (5%-10%), gastrointestinal tract (5%-10%), and central nervous system (5%).

Managing extramedullary plasmacytoma typically involves a combination of surgery, radiation therapy, and chemotherapy. Conjunctival involvement, as seen in this case, is extremely rare. In our case, the patient underwent successful excision of the conjunctival mass and ocular surface reconstruction with amniotic membrane. He showed no signs of recurrence at one-year follow-up. The patient is currently advised to undergo close observation every six months to look for any late recurrences, if any, which can occur even after many years.

CONCLUSION

In conclusion, this case report highlights the importance of considering multiple myeloma in the differential diagnosis of ocular masses, particularly in patients with a known history of the disease. A multidisciplinary approach, including ophthalmology, medical oncology, and pathology, is essential for accurate diagnosis and effective management of such rare and complex cases. The use of intraoperative frozen section in this case was crucial, as it enabled us to differentiate the conjunctival mass from OSSN, which was our initial clinical suspicion. This timely diagnosis allowed for prompt and appropriate management, underscoring the value of intraoperative frozen section in guiding surgical decisions.