Dr. Apjit Kaur
King George’s Medical University
Lucknow
Ocular Adnexal Lymphoma
The American Academy of Ophthalmology reported a review of literature on Ocular Adnexal Lymphoma. Michael T Yen et al reviewed the current treatment options, evaluating the outcomes and complications related to therapy. The authors followed the rating scale developed by the Oxford Centre for Evidence-Based Medicine.
Orbital lymphomas present as painless, slowly progressive swelling, causing proptosis without visual loss and diplopia. Conjunctival lesions are pinkish, referred to as Salmon patch. The orbit is affected by all subtypes of Lymphoma, commonest being extra nodal marginal zoneB cell lymphoma of mucosa associated lymphoid tissue (MALT). Biopsy helps in identification of histologic subtype and risk stratification.
Studies of MALT lymphoma treated with radiotherapy reported very good outcome when it was used alone or in combination with chemotherapy.. Mean dose of radiation used was 32.8 Gy (4-50 Gy). The 5 year and 10 year disease free survival of MALT lymphoma was 86.4% and 78.7% respectively. Studies on mixed histologic types reported local control rates of 93.1% with radiotherapy and disease free survival rates of 75.7% and 71.0% for 5 nd 10 year period respectively.
Use of chemotherapy or immune modulation in addition to radiotherapy was reported for advanced disease, relapsed disease or non-MALT lymphoma in some studies. There were no studies of Level 1 evidence for comparison. Cyclophosphamide, doxorubicin, vincristine and prednisone were the most commonly used chemotherapeutic agents. MALT lymphoma showed better therapeutic response as compared to follicular lymphoma and diffuse large B cell lymphoma.
MALT Lymphoma , treated with Doxycycline, showed local complete response in an average of 8.7% patients. Thus far less effective than radiotherapy.
Thus MALT lymphoma can be locally controlled by radiotherapy, either in isolation or combination with chemotherapy. Influence on long term survival rates may be beneficial. Other types of Lymphomas do not respond as well as MALT type with either radiotherapy or combination. Doxycycline seems to have limited role.
Further Reading: Yen MT, Bilyk JR, Wladis EJ, Bradley EA, Mawn LA. Treatments for Ocular Adnexal Lymphoma: A Report by the American Academy of Ophthalmology. Ophthalmology. 2018;125(1):127-136.
Stem Cells in Oculoplasty
Micheal G Daniel and Albert Y Wu reviewed the utility of stem cells in Oculoplastic surgery.
Embryonic stem cells (ESC) and induced pluripotent (iPSC) stem cells self renew and can form different cell lineages. This generates the potential for them to be used as alternatives in tissue reconstruction and remodeling.
Lacrimal Gland, Orbital fat and muscles and limbal tissue have resident stem cells. The accessibility of these structures permits the ease of treatment. These have been used for in vitro cell and organ cultures.
Stem cell biology has been applied to eyelid reconstruction surgeries, lacrimal gland development, tissue reconstruction after tumor resection, and cosmetic procedures. Patient specific stem cells may possibly provide alternatives to damaged tissues and organs.
Nestin and Ki67 are expressed by the resident stem cells of the lacrimal gland. They repair the lacrimal gland damaged due to inflammatory process. It has been reported that bioengineered lacrimal gland made of epithelial and mesesnchymal cells of E16.5 mouse, adopted the structure of lacrimal gland in vitro. They have thus a role in the management of dry eyes. This could also be done with the somatic cells of the lacrimal gland of patients with damaged lacrimal glands.
Surgical repair of eyelid and peri-ocular tumor resection defects is challenging. Stem cell biology finds application in generating autologous grafts from patient specific cells. This overcomes the major hurdle of graft rejection. Adipose derived stem cells (ADSC) are easily acquired and have the potential to differentiate into several types of cells. Unlike the ADSCs of the rest of the body that are mesenchymal in origin, the orbital ADSCs are derived from the neural crest. This may allow their use in ocular surface reconstruction and retinal dystrophies.
ADSCs could also be used to regenerate tissues like conjunctiva and tarsus via reprogramming. Cosmetic surgery has found great application of benefits from stem cell biology. Photo -damaged skin rejuvenation has been revolutionized by use of ADSCs.
Further Reading:
Daniel M, Wu A. Applications of stem cell biology to oculoplastic surgery. Curr Opin Ophthalmol. 2016.27(5): 428–432.