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CASE REPORT |
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Year : 2015 | Volume
: 8
| Issue : 5 | Page : 653-655 |
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Black pancreatic neuro-endocrine tumor: A rare finding
Shailja Puri Wahal, Neha Mohindroo, Shobla Mohindroo
Department of Pathology, Indira Gandhi Medical College, Shimla, Himachal Pradesh, India
Date of Web Publication | 10-Sep-2015 |
Correspondence Address: Shailja Puri Wahal Department of Pathology, Indira Gandhi Medical College, Shimla - 171 001, Himachal Pradesh India
Source of Support: Nil., Conflict of Interest: None declared. | Check |
DOI: 10.4103/0975-2870.164951
Pigmented lesions most commonly encountered in any organ are due to deposition of melanin in primary or metastatic malignant melanoma. Other less common pigments are lipofuscin and neuromelanin. Lipofuscin and neuromelanin are usually associated with benign lesions. Differentiating melanin from lipofuscin and neuromelanin is important as the former is usually associated with malignancy. However, melanin can occur in benign lesion also. All there pigments are differentiated by histopathological examination, histochemical stain, and immunohistochemistry. Black pigment is associated with black adenoma of the adrenal gland, neuro-endocrine tumor of lung, and foregut; however, it is rarely seen in neuro-endocrine tumor of the pancreas. We report a case of 61-year-old male patient with neuro-endocrine tumor of the pancreas associated with extensive deposition of black-colored melanin pigment. Keywords: Lipofuscin, melanin, neuromelanin, pancreatic neuro-endocrine tumor
How to cite this article: Wahal SP, Mohindroo N, Mohindroo S. Black pancreatic neuro-endocrine tumor: A rare finding. Med J DY Patil Univ 2015;8:653-5 |
Introduction | | |
Pigmented tumors are extremely rare in pancreas. When black pigment is encountered, it often suggests the presence of metastatic malignant melanoma. We report a case of melanin deposition in a neuro-endocrine tumor of the pancreas. Melanin deposition is seen in adenoma of the adrenal gland called black adenoma; however, it is rare in pancreas. We present this case due to its rarity with review of the literature.
Case Report | | |
A 61-year-old man presented with a mass in the pancreas. Computed tomography showed an area of heterogeneous density in the body of the pancreas [Figure 1]a. A clinical diagnosis of pancreatic neoplasm was kept and pancreatic mass, peri-pancreatic lymph node and spleen were surgically excised. Grossly, irregular tan-brown pancreatic mass was received measuring 7.5 cm × 3.5 cm × 1.5 cm. The peri-pancreatic lymph node measured 2 cm in diameter and spleen measured 7 cm × 4 cm × 1.5 cm. Cut surface of the mass was gray-white to tan-brown in color. Microscopic examination showed tumor cells disposed in solid sheets, ribbons, and festoons separated by highly vascularized stroma. Individual cells were uniform, small cuboidal cells with centrally located nucleus and acidophilic cytoplasm. Deposits of black pigment were present in and around the tumor cells [Figure 1]b. Pseudo-rosettes were also evident at places. The lymph node also showed metastasis from tumor cells with black colored pigment [Figure 1]c. The spleen was free from tumor cell invasion. The tumor cells in the pancreatic mass and lymph node demonstrated a positive reaction with Fontana-Masson (FM) stain [Figure 1]d which was susceptible to bleaching and a negative reaction to iron stain. The tumor cells were immune-reactive for chromogranin A and negative for HMB-45. A diagnosis of pancreatic neuro-endocrine tumor with black melanin pigment was given. | Figure 1: (a) Computed tomography scan showing a heterogeneous density in the body of pancreas. (b) The tumor cells disposed in solid sheets, ribbons, and festoons. Individual cells are uniform, small cuboidal cells with centrally located nucleus and acidophilic cytoplasm. Some of the tumor cells show deposition of black pigment (H and E, ×40). (c) Lymph node shows metastatic tumor cell deposits with black pigment (H and E, ×40). (d) The pigment containing tumor cells in the pancreatic mass stain strongly with Fontana-Masson (×40)
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Discussion | | |
Black-colored pigmented has been described in a variety of organs both macroscopically and microscopically. Melanin, a brown-black pigment derived from tyrosine has been described in malignant melanoma, dermatofibromasarcoma protuberance, medullary thyroid carcinoma, neuro-endocrine tumor of thymus, melanotic schwannoma, melanocytic tumors of esophagus, carcinoid of the lung, adenocarcinoma of rectum, and paraganglioma of uterus. Ultrastructural examination reveals melanosomes and premelanosomes in melanin-containing tumor cells.[1] Lipofuscin is a wear and tear pigment and appears brown-yellow on hematoxylin and eosin staining. Lipofuscin pigment has been reported in black thyroid syndrome, in pigmented extra-adrenal paraganglioma, in pigmented renal cell carcinoma, pigmented hepatocellular carcinoma, and prostatic melanosis. Ultrastructurally, lipofuscin consists of the membrane bound, electron dense, intracytoplasmic granules with fat droplets.[1] Neuromelanin is a brown-black pigment found in neurons of substantia niagra and locus ceruleus and sympathetic ganglion cells. Ultrastructurally, neuromelanin consists of the membrane bound, electron dense, intracytoplasmic granules with or without fat droplets.[2] All three pigments, melanin, lipofuscin, and neuromelanin show a positive reaction with FM stain. Melanin and neuromelanin are susceptible to bleaching; however, lipofuscin may be resistant to bleaching.
Pigmented pancreatic tumors are rare. The presence of black pigment in pancreatic mass suggests primary malignant melanoma or metastatic melanoma. However, histological examination of the tumor mass, cytochemical staining and unreactive immunohistochemistry for HMB-45 rules out the possibility of primary or metastatic melanoma. A similar tumor called "black adenoma" is described in the adrenal gland by Lack.[3] "Black adenoma" of the adrenal gland is radiologically and histologically similar to pigmented pancreatic tumor. This is diffusely pigmented or black in color macroscopically. Microscopically, it consists of lipofuscin or neuromelanin.
The cause of deposition of these pigments is not known. Melanin is seen in malignant melanoma and other melanocytic lesions. Lipofuscin is a wear and tear pigment, and its presence signifies a degenerative process. Neuromelanin is ultrastructurally similar to lipofuscin. Some studies have shown neuromelanin to be partially melanized lipofuscin giving rise to a novel term "lipomelanin."[4] Differentiation of lipofuscin and neuromelanin may be difficult but it is more important to differentiate both these pigments from melanin due to the association of melanin with malignancy. Lipofuscin and neuromelanin are more often seen in benign lesions.
Pigmented neuro-endocrine tumors are reported in lung, but occurrence in the pancreas is rare. Presence of pigment in pancreatic neuro-endocrine tumor draws attention towards the embryonic development of the latter. The pancreatic neuro-endocrine cells or the islets share many functional properties with neurons. Appearance of pigments in neuro-endocrine tumor is phenotypic representation of reappearance of embryonic trait; however, this hypothesis needs to be proved by more studies.[5] Besides lung, pigmented neuro-endocrine tumors of the fore gut are also known to occur. The origin of these tumors is the multipotent precursor cells. The pancreatic neuro-endocrine tumors are also known to arise from these multipotent precursor cells; however, pigments are rarely seen in them.
To conclude, black pigments in pancreatic tumors should be differentiated from melanoma and other melanocytic lesions. Careful histopathological, histochemical, immunohistochemical, and ultrastructural examination help to know the true nature of the pigmented lesion.
References | | |
1. | Smith AE, Levi AW, Nadasdy T, Campbell KA, Fishman EK, Hruban RH. The pigmented "black" neuroendocrine tumor of the pancreas: A question of origin. Cancer 2001;92:1984-91. |
2. | Iihara K, Yamaguchi K, Fujioka Y, Uno S. Pigmented neuroendocrine tumor of the lung, showing neuromelanin. Pathol Int 2002;52:734-9. |
3. | Lack EE. Tumors of the adrenal gland and extra-adrenal paraganglia. In: Rosai J, editor. Atlas of Tumor Pathology. 3 rd ed. Washington, DC: Armed Forces Institute of Pathology; 1997. p. 102-5. |
4. | Barden H. The histochemical relationship of neuromelanin and lipofuscin. J Neuropathol Exp Neurol 1969;28:419-41. |
5. | Teitelman G. On the origin of pancreatic endocrine cells, proliferation and neoplastic transformation. Tumour Biol 1993;14:167-73. |
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