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Biomedical subjects

A D Singh

Publications and source records attributed to A D Singh.

At least 19 recordsLinked to original sources
PubMed2001

Adenocarcinoma arising from congenital hypertrophy of retinal pigment epithelium.

Congenital hypertrophy of the retinal pigment epithelium (CHRPE), traditionally regarded as a benign stationary condition, has recently been shown in 5 cases to give rise to an elevated, solid tumor. However, the histopathologic nature of the tumor that arises from CHRPE has not been previously determined. A 65-year-old woman developed a progressively enlarging peripheral fundus tumor that arose from a focus of classic CHRPE. The tumor produced a localized exudative retinal detachment, cystoid macular edema, and surface-wrinkling retinopathy. The mass was removed by local resection, and histopathologic examination revealed a low-grade adenocarcinoma of the retinal pigment epithelium, apparently arising from CHRPE. Although CHRPE is usually a benign nonprogressive lesion, it can give rise to a malignant tumor. Congenital hypertrophy of the retinal pigment epithelium should be observed periodically for development of a neoplasm.

Adenocarcinoma↗
PubMed2001

Iris melanoma: risk factors for metastasis in 169 consecutive patients.

OBJECTIVE: To identify risk factors that predict distant metastases of iris malignant melanoma. DESIGN: Retrospective case series. PARTICIPANTS: The participants included 169 consecutive patients with microscopically confirmed iris malignant melanoma managed on the Oncology Service at Wills Eye Hospital between 1974 and 1999. MAIN OUTCOME MEASURES: The main outcome measure was the development of distant tumor metastasis. Cox proportional regression models were used to calculate the risk of eventual metastatic spread. RESULTS: Of 1054 patients referred with suspicious iris melanocytic tumors (rule out malignant melanoma) over a 25-year period, 169 patients (16%) had microscopically proven iris melanoma, and the remainder (84%) had clinically diagnosed iris nevus. Of the patients with iris melanoma, the mean age at the time of diagnosis was 43 years (median, 45 years; range, 1-90 years). All patients were Caucasian. The mean tumor base was 6 mm (median, 5 mm; range, 1-17 mm), and mean tumor thickness was 2 mm (median, 2 mm; range, 1-4 mm). The mean number of clock hours of tumor involvement in the iris was four, tumor seeding on the iris was four, and tumor seeding into the anterior chamber angle was four. Extraocular extension was present in 10 eyes (6%). The tumor management consisted of local resection (iridectomy, iridocyclectomy, or iridocyclogoniectomy) in 102 patients (60%), enucleation in 51 (30%), plaque radiotherapy in 9 (5%), and observation in 7 patients (4%). Metastasis developed in nine patients (5%). Using Kaplan-Meier life table analysis, metastasis was found in 3% of patients at 5 years, 5% at 10 years, and 10% at 20 years. The clinical factors at initial evaluation predictive of eventual metastasis from iris melanoma included increasing age at diagnosis (P = 0.03), elevated intraocular pressure (P = 0.03), posterior tumor margin at angle or iris root (versus midzone) (P = 0.02), extraocular extension (P: = 0.02), and prior surgical treatment of the tumor elsewhere before referral (versus observation) (P = 0.006). The method of management (resection, radiotherapy, or enucleation) did not have an impact on metastasis. CONCLUSIONS: Microscopically confirmed iris melanoma demonstrates distant metastasis in 5% of patients at 10 years follow-up. Metastases are more likely to develop in those patients who are older and show tumor features of iris root/angle location with elevated intraocular pressure and extraocular extension.

Adolescent↗
PubMed2001

Orbital malignant fibrous histiocytoma following irradiation for retinoblastoma.

PURPOSE: An unusual case is reported of orbital malignant fibrous histiocytoma that developed after irradiation for retinoblastoma. METHODS: Case report. RESULTS: A 5-month-old girl underwent enucleation of the left eye, external beam irradiation of the right eye, and systemic chemotherapy for bilateral sporadic retinoblastoma. At age 17 years, a malignant fibrous histiocytoma developed in the medial aspect of the orbit and nasal cavity. After attempted excisional biopsy, she underwent craniofacial resection, orbital exenteration, maxillectomy, and tracheostomy. The patient was alive 12 months postoperatively without local or metastatic disease. CONCLUSIONS: Although orbital fibrous histiocytoma occurs usually as a primary tumor of adulthood, it can also develop as a secondary tumor after irradiation for retinoblastoma.

Biopsy↗
PubMed2001

Central retinal vascular obstruction secondary to melanocytoma of the optic disc.

A 35-year-old black man developed abrupt visual loss in his left eye. Ophthalmic examination revealed a deeply pigmented mass obscuring the optic disc, hemorrhagic retinopathy, and signs of central retinal vascular obstruction. Fluorescein angiography disclosed sluggish filling of the retinal blood vessels; ultrasonography disclosed an acoustically solid mass in the optic nerve head. Cytopathologic findings of a fine needle aspiration biopsy specimen demonstrated probable benign tumor cells, but melanoma could not be excluded. Histopathologic findings in the enucleated eye revealed a large, necrotic melanocytoma of the optic disc and hemorrhagic necrosis of the retina secondary to obstruction of the central retinal artery and vein. Melanocytoma of the optic nerve can undergo spontaneous necrosis and induce central retinal vascular obstruction. Abrupt visual loss in a patient with a melanocytoma does not necessarily imply malignant transformation.

Adult↗
PubMed2000

Observations on 17 patients with retinocytoma.

OBJECTIVE: To study the clinical features and natural history of 17 patients with retinocytoma. DESIGN: A retrospective case series. SETTING: Tertiary referral center. PATIENTS: Data on 17 patients with retinocytoma were reviewed for clinical features. The natural history of retinocytoma and its risk for malignant transformation were also evaluated. RESULTS: Among 920 consecutive patients who had retinoblastoma, retinocytoma, or both, we identified 24 tumors in 17 patients (1.8%) with clinical features compatible with retinocytoma. The median age at diagnosis was 15 years (range, 4-45 years). Of the 24 tumors, the retinocytoma was bilateral in 3 cases (13%) and the family history of retinoblastoma was positive in 3 cases (13%). Seventeen (71%) of the tumors were extramacular in location, and 7 (29%) were located in the macular area. Ophthalmoscopic features characteristic of retinocytoma included the presence of a translucent retinal mass in 21 (88%), calcification in 15 (63%), and retinal pigment epithelial alteration in 13 (54%) of the 24 tumors. A combination of all 3 features was observed in 8 (33%) of the 24 tumors. In 13 (54%) of the tumors, a zone of chorioretinal atrophy could be observed. In 1 patient, subtle tumor regression was documented photographically. Only 1 retinocytoma (4%) underwent malignant transformation into retinoblastoma. At the last follow-up visit, none of the patients had developed a pineoblastoma or another second malignant neoplasm. CONCLUSIONS: Retinocytoma is a rare benign retinal tumor that has characteristic clinical features. The areas of chorioretinal atrophy were suggestive of tumor regression. In our series, the risk for malignant transformation of retinocytoma into retinoblastoma was 4%; therefore, patients with a presumed diagnosis of retinocytoma should be closely observed.

Adolescent↗
PubMed2000

Metastatic neoplasms in the optic disc: the 1999 Bjerrum Lecture: part 2.

BACKGROUND: Little information is available on metastatic tumors to the optic disc. OBJECTIVE: To determine the clinical features and prognosis of patients with optic disc metastasis. DESIGN: Retrospective chart review. RESULTS: Of 660 consecutively evaluated patients with intraocular metastasis, 30 (4.5%) (31 eyes) had metastatic cancer to the optic disc; 24 (80%) were women and 6 (20%) were men. Mean age at the time of ocular diagnosis was 55 years. The primary neoplasm was in the breast in 13 patients (43%), in the lung in 8 (27%), in the intestine in 1 (3%), in the kidney in 1 (3%), and in the prostate in 1 (3%); the primary neoplasm was never determined in 6 patients (20%). The optic disc metastasis was unilateral in 29 patients (97%) and bilateral in 1 (3%). Ophthalmoscopically, the disc metastasis appeared as a diffuse enlargement of the optic disc in 26 eyes (84%) and as a distinct nodule in 5 (16%). There was an adjacent juxtapapillary choroidal component to the metastatic disc lesion in 23 eyes (74%), and the optic disc was involved without a retinal or choroidal component in 8 (26%). Other associated findings included some degree of secondary disc edema in all eyes, buried disc blood vessels in 23 (74%), and splinter hemorrhages in 13 (42%). Fine needle aspiration biopsy was useful in establishing the diagnosis in all 5 eyes in which it was performed. Mean survival was 13 months after diagnosis of the disc metastasis. CONCLUSIONS: Metastasis to the optic disc accounts for 5% of all intraocular metastases. It can occur as invasion from a juxtapapillary choroidal metastasis or as isolated optic disc metastasis. Breast and lung cancers are the most common primary neoplasms that account for metastasis to the optic disc. The primary site is never determined in 20% of patients. The characteristic clinical features of optic disc metastasis should help differentiate it from other causes of swollen optic disc. Patient prognosis is poor.

Adult↗
PubMed2000

Combination of clinical factors predictive of growth of small choroidal melanocytic tumors.

OBJECTIVE: To better define the effect of individual risk factors and combinations thereof on the growth of small choroidal melanocytic tumors. DESIGN: Retrospective analysis. SETTING: Clinical practice of ocular oncology. PATIENTS: The study included 1287 patients with small suspicious choroidal melanocytic tumors, measuring 3 mm or less in thickness, managed with observation. RESULTS: On multivariate analysis, the clinical risk factors predictive of growth of small choroidal melanocytic tumors include tumor thickness greater than 2.0 mm, posterior tumor margin touching the disc, visual symptoms, orange pigment, and subretinal fluid. Tumor growth was detected in 4% of those patients with no risk factors. Growth was detected in approximately 36% of patients with 1 risk factor, 45% of patients with 2 risk factors, 50% of patients with 3 risk factors, 51% of patients with 4 risk factors, and 56% of patients with all 5 risk factors. The combination of risk factors offering the greatest risk for growth was tumor thickness greater than 2.0 mm, tumor margin touching disc, and subretinal fluid that was associated with tumor growth in 63% of the affected patients. The relative risk for growth was 1.9 for 1 factor, 3.8 for 2 factors, 7.4 for 3 factors, 14.1 for 4 factors, and 27.1 for all 5 risk factors combined. CONCLUSIONS: Five risk factors for growth of small choroidal melanocytic tumors have been identified. The combinations of various factors increase the risk for tumor growth from 4% if no factors are present to more than 50% if 3 or more risk factors are present. These factors may be important when counseling patients with small suspicious choroidal melanocytic tumors.

Choroid Neoplasms↗
PubMed2000

Acquired tumors arising from congenital hypertrophy of the retinal pigment epithelium.

BACKGROUND: Congenital hypertrophy of the retinal pigment epithelium (CHRPE) is widely recognized to be a flat, stationary condition. Although it can show minimal increase in diameter, it has not been known to spawn nodular tumor that is evident ophthalmoscopically. OBJECTIVES: To report 5 cases of CHRPE that gave rise to an elevated lesion and to describe the clinical features of these unusual nodules. METHODS: Retrospective medical record review. RESULTS: Of 5 patients with a nodular lesion arising from CHRPE, there were 4 women and 1 man, 4 whites and 1 black. Three patients were followed up for typical CHRPE for longer than 10 years before the tumor developed; 2 patients were recognized to have CHRPE and the elevated tumor concurrently. Visual acuity was decreased in 3 patients, mainly due to cystoid macular edema. The tumor was located between the equator and ora serrata in all 5 patients. There was no predilection for quadrant of the fundus. The flat part of the lesion was black and had visible lacunae in all 5 patients. The CHRPE ranged in basal diameter from 3 x 3 mm to 13 x 11 mm. The size of the elevated lesion ranged from 2 x 2 x 2 mm to 8 x 8 x 4 mm. The nodular component in all cases was supplied and drained by slightly prominent, nontortuous retinal blood vessels. Yellow retinal exudation occurred adjacent to the nodule in all 5 patients and 1 patient developed a secondary retinal detachment. Two tumors that showed progressive enlargement, increasing exudation, and progressive visual loss were treated with iodine 125-labeled plaque brachytherapy, resulting in deceased tumor size but no improvement in the visual acuity. CONCLUSIONS: Congenital hypertrophy of the retinal pigment epithelium can spawn a nodular growth that slowly enlarges, attains a retinal blood supply, and causes exudative retinopathy and chronic cystoid macular edema. Although no histopathologic evidence is yet available, we believe that the tumor probably represents either an acquired adenoma or a reactive proliferation of the retinal pigment epithelium. The best treatment of these lesions is not yet established.

Adenoma↗
PubMed2000

Iris mammillations as the only sign of ocular melanocytosis in a child with choroidal melanoma.

An 8-year-old girl had visual loss in her left eye over 2 months. Ocular examination showed that visual acuity was counting fingers in the left eye. The left iris was moderately pigmented and thickened with numerous confluent, dome-shaped elevations on its surface, consistent with iris mammillations arising from ocular melanocytosis. There was total retinal detachment and an inferiorly located large amelanotic choroidal mass compressing the optic nerve. A specimen from a fine-needle aspiration biopsy showed spindle and epithelioid melanoma cells. The eye was enucleated. Pathologic examination showed that the bland melanocytes comprising the anterior border layer of iris formed focal aggregates, corresponding to the iris mammillations observed clinically. The uvea was diffusely thickened. Arising from the posterior choroid and obscuring the optic nerve head was a moderately pigmented spindle and epithelioid cell choroidal melanoma with diffuse lymphocytic infiltration and high mitotic activity. This case demonstrates that iris mammillations can be the initial manifestation of ocular melanocytosis in the absence of scleral pigmentation.

Child↗
PubMed2000

Systemic amyloidosis presenting as a mass of the conjunctival semilunar fold.

PURPOSE: To report a case of systemic amyloidosis that presented as a mass of the plica semilunaris (semilunar fold) of the conjunctiva. METHODS: Case report. RESULTS: A healthy 56-year-old man developed a fleshy, hemorrhagic lesion of the semilunar fold of the left conjunctiva. Excisional biopsy revealed an acellular lesion of the conjunctival stroma that stained positively for Congo red and showed apple-green birefringence and dichroism with polarization microscopy. The diagnosis was amyloidosis of the semilunar fold of the conjunctiva. Subsequent evaluation disclosed systemic amyloidosis. The patient remains asymptomatic. CONCLUSIONS: Although conjunctival amyloidosis usually occurs as a localized lesion without systemic involvement, it can be the initial sign of systemic amyloidosis.

Amyloidosis↗
PubMed2000

Concurrent choroidal melanoma in son and father.

PURPOSE: To report the concurrent occurrence of choroidal melanoma in a son and father. METHODS: Case reports. The likelihood of familial occurrence of uveal melanoma in which father and son are affected was estimated using the principles of probability. RESULTS: Unilateral choroidal melanoma was diagnosed in a 41-year-old man. Three months later, his 68-year-old father presented with a pigmented choroidal mass that greatly increased in size during the next 6 months and was diagnosed a choroidal melanoma. No personal or family history of atypical moles, cutaneous melanoma, or other malignancy existed. The likelihood of familial occurrence of uveal melanoma using principles of probability was estimated to be 1 in 10 million. CONCLUSION: Considering the low prevalence of uveal melanoma in the general population, the likelihood of uveal melanoma occurring in a family setting is remote.

Adult↗
PubMed2000

Cutaneous capillary hemangiomas of the eyelid, scalp, and digits in premature triplets.

PURPOSE: To document the unique occurrence of multiple cutaneous capillary hemangiomas in healthy triplets. METHODS: Case reports. RESULTS: Triplets born 6 weeks prematurely were noted at birth to have classic cutaneous capillary hemangiomas that enlarged in the first few months of life. At 3 months of age, triplet #1 manifested a small capillary hemangioma on the left index finger and a large hemangioma that involved the entire left upper eyelid and completely occluded the visual axis. Triplet #2 had a small hemangioma on the thumb and a large hemangioma on the scalp of the forehead. Triplet #3 displayed only a minor hemangioma of the right upper eyelid that did not threaten her vision. The parents of the triplets admitted having a history of periocular capillary hemangioma that spontaneously resolved. Triplet #1 was managed with oral corticosteroids, with dramatic regression of the mass and exposure of the visual axis. CONCLUSIONS: Cutaneous capillary hemangioma is usually a sporadic condition. We found this tumor in premature triplets whose parents had a history of a similar tumor. This suggests that hereditary and environmental factors may play a role in the development of this tumor. We advise that medical and family histories be obtained in all children with cutaneous capillary hemangioma.

Eyelids↗
PubMed2000

Non-traumatic rhabdomyolysis with acute renal failure.

A clinical profile of non-traumatic rhabdomyolysis with acute renal failure is presented. Myoglobinuric renal failure is treatable and hence a high index of suspicion is warranted in the etiologies discussed.

Acute Kidney Injury↗