J Cutan Pathol 2014: 41: 783–786 doi: 10.1111/cup.12373 John Wiley & Sons. Printed in Singapore
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Journal of Cutaneous Pathology
Nail bed onychomatricoma Onychomatricoma is a rare tumor originating from the nail matrix, and, in rare conditions, from the ventral aspect of the proximal nailfold. Here we report a rare case of a 51-year-old man presenting with melanonychia mainly involving the distal nail plate. Histopathologic examination showed typical findings of onychomatricoma mainly involving the nail bed, while the nail matrix was largely uninvolved. We also identified fungal infection in a focal area of the distal nail plate. Our findings indicate that onychomatricoma can develop in the surrounding epithelial tissue of the nail unit, including the nail bed, and suggest that fungal infection may represent a secondary phenomenon of onychomatricoma. Keywords: fungus, nail bed, nail matrix, onychomatricoma Wang L, Gao T, Wang G. Nail bed onychomatricoma. J Cutan Pathol 2014; 41: 783–786. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Onychomatricoma is a rare tumor originating predominantly from the nail matrix.1 To date, only approximately 70 cases have been reported,2 most of them by Perrin et al.3 – 7 Onychomatricoma typically presents as longitudinal rough yellow bands and a thickened nail plate with splinter hemorrhages,1,3 or sometimes as a cutaneous horn3,8,9 or pterygium of the dorsal nail.5 Histopathologically, onychomatricoma is characterized by abnormal proliferation of basophilic epithelioid cells usually involving the nail matrix, accompanied by a thickened nail plate.1 – 7 In rare cases, the ventral aspect of the proximal nailfold has been reported to be involved.5 Herein, we present a rare case of onychomatricoma mainly involving the nail bed, which was associated with fungal infection of the abnormal nail plate. Report of a patient A 51-year-old man presented with a thickened black band in his left thumbnail. The lesion was asymptomatic and had enlarged gradually over the past 7 years. In the month prior to admission, the patient had experienced slight pain at the site of the lesion. Clinical examination showed a dark brown longitudinal band in the center
A
Lei Wang, Tianwen Gao and Gang Wang Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xian, China Gang Wang, MD, PhD and Tianwen Gao, MD, PhD Department of Dermatology Xijing Hospital Fourth Military Medical University No. 127 of Changlexi Rd Xian 710032 China Tel: +86 2984775401 Fax: +86 2984775401 e-mails: [email protected]; [email protected] Accepted for publication June 28, 2014
B
Fig. 1. A) A longitudinal black band mainly involving the distal nail plate was observed. B) Frontal view of the thickened and fragile distal nail plate.
of the nail (Fig. 1A). The nail plate became darker and thicker toward the distal part, and was splintered (Fig. 1B). Materials and methods The whole nail unit was removed for microscopic examination. The lesion was fixed in 10% buffered formalin for 24 h and subsequently
783
Wang et al. A
B
C
D
E
F
G
H
Fig. 2. A) Scanning magnification showing the whole nail unit. B) Low magnification showing that the nail matrix was largely uninvolved. C) High magnification showing a small cyst with several layers of basophilic cells and a prominent granular layer. D) Low magnification showing papilated proliferation of nail matrix cells and thickening of the nail plate. Infiltration of lymphocytes in the dermis was also observed. E) Intermediate magnification of the proximal nail bed showing V-shaped proliferation of basophilic cells, which translated into eosinophilic cells and then into a pink nail plate. F) Intermediate magnification of the distal nail bed showing similar histopathology. G) High magnification of the proximal nail bed showing the translation from matrix cells to nail plate. H) High magnification of the distal nail bed showing the translation from eosinophilic cells to nail plate.
in 10% ethylenediaminetetraacetic acid (EDTA) for 1 week of decalcification. The tissue was then embedded in a longitudinal direction, and the sections were stained with hematoxylin and eosin, and with periodic acid-Schiff (PAS) prior to examination.
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Results The scanning magnification of the longitudinal appearance of the whole nail unit is shown in Fig. 2A. The proximal nail matrix and the proximal nail plate appeared normal (Fig. 2B), except for two small cystic structures located
Nail bed onychomatricoma A
B
C
D
Fig. 3. Schematic diagrams of (A) a normal nail unit; (B) onychomatricoma of the nail matrix5 ; (C) onychomatricoma of the nailfold5 ; and (D) onychomatricoma of the nail bed. Clinically, onychomatricoma can present as B, C, D, or a combination thereof (red: nail matrix; blue: nailfold and nail bed; beige: nail plate).
in the superficial dermis (Fig. 2C). There was papillomatous proliferation of basophilic epithelioid cells in the nail bed, and thickening of the distal nail plate (Fig. 2D), with the proximal nail bed showing a more prominent papillomatous appearance (Fig. 2E) than the distal part (Fig. 2F). In the proximal part of the nail bed, the proliferated basophilic cells transformed into eosinophilic cells, and then into a pink cornified nail plate (Fig. 2G). The histopathology of the distal part was similar to that of the proximal part of the nail bed, except that the papillomatous appearance of the epithelial cells was very subtle (Fig. 2H). In the dermis, there was no prominent fibroblast proliferation, and scattered lymphocyte infiltration was observed. Scattered blood serum was present in the abnormally thick nail plate (data not shown). In the distal nail plate adjacent to the hyponychium, we noticed fungal hyphae and spores in a focal area, which were more prominent upon Periodic Acid-Schiff staining. We also noticed hyphae and spores in a focal area of the stratum corneum of the hyponychium (data not shown). Discussion Onychomatricoma is recognized as a benign neoplasm originating from or differentiating toward nail matrix cells. Histopathologically, it usually involves the nail matrix, and may, in rare cases, involve the ventral aspect of proximal nailfold. The case presented herein shows
that onychomatricoma can develop from the nail bed; we believe that these results will help to increase our understanding of the histopathology of this rare disease. In our case, only the distal part of the nail plate was thickened, whereas the proximal nail plate appeared normal (Fig. 1). The clinical appearance was consistent with the microscopic findings, which showed a prominent papillomatous appearance of the nail bed, while the nail matrix was largely uninvolved. Perrin et al.5 reported onychomatricoma involving the nailfold near the nail matrix, which presented clinically as dorsal pterygium. According to their findings and our current observations, onychomatricoma can develop in both the nail matrix and the surrounding tissues, including both the ventral aspect of proximal nailfold and the nail bed (Fig. 3A–D). In this case, we found that the nail matrix was largely uninvolved, though two small cystic structures in the dermis under the normal nail matrix were noted. The cysts comprised basophilic cells at the periphery and a focal granular layer (Fig. 2C). It is unclear if this structure represented onychomatricoma at a very early stage. The proliferation of matrix cells in the nail bed and proximal nailfold may be caused by metaplasia.5 We propose that the inflammation in the dermis of our case may possibly lead to the metaplasia of nail bed cells. Others have suggested a role for fungal infection in the development of onychomatricoma, which has been detected by culture in a small number of cases.8,10 According to our results, the fungal infection was limited to a very focal area adjacent to the hyponychium; thus, we infer that the fungal infection was not a causative factor, but rather a secondary phenomenon of onychomatricoma. In the abnormal nail plate, we identified scattered blood serum, accounting for the black color of the lesion. This phenomenon has previously been described by Fayol et al.8 In conclusion, we have reported on a rare case of onychomatricoma of the nail bed associated with incidental fungal infection. Acknowledgements We would like to thank Dr Shi Yan for helping with the preparation of Fig. 3.
References 1. Baran R, Kint A. Onychomatrixoma: filamentous tufted tumour in the matrix of a
funnel-shaped nail: a new entity (report of three cases). Br J Dermatol 1992; 126: 510.
2. Cloetingh D, Helm KF, Ioffreda MD, Billingsley E, Rubin AI, Haneke E. JAAD
785
Wang et al. grand rounds quiz Onychomatricoma. J Am Acad Dermatol 2014; 70: 395. 3. Perrin C, Goettmann S, Baran R. Onychomatricoma: clinical and histopathologic findings in 12 cases. J Am Acad Dermatol 1998; 39: 560. 4. Perrin C, Baran R, Pisani A, Ortonne JP, Michiels JF. The onychomatricoma: additional histologic criteria and immunohistochemical study. Am J Dermatopathol 2002; 24: 199.
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5. Perrin C, Baran R. Onychomatricoma with dorsal pterygium: pathogenic mechanisms in 3 cases. J Am Acad Dermatol 2008; 59: 990. 6. Perrin C, Baran R, Balaguer T, et al. Onychomatricoma: new clinical and histological features. A review of 19 tumors. Am J Dermatopathol 2010; 32: 1. 7. Perrin C, Langbein L, Schweizer J, et al. Onychomatricoma in the light of the microanatomy of the normal nail unit. Am J Dermatopathol 2011; 33: 131.
8. Fayol J, Baran R, Perrin C, Labrousse F. Onychomatricoma with misleading features. Acta Derm Venereol 2000; 80: 370. 9. Gaertner EM, Gordon M, Reed T. Onychomatricoma: case report of an unusual subungual tumor with literature review. J Cutan Pathol 2009; 36S1: 66. 10. Piraccini BM, Antonucci A, Rech G, Starace M, Misciali C, Tosti A. Onychomatricoma: first description in a child. Pediatr Dermatol 2007; 24: 46.
This document is a scanned copy of a printed document. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material.
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Journal of Cutaneous Pathology
Nail bed onychomatricoma Onychomatricoma is a rare tumor originating from the nail matrix, and, in rare conditions, from the ventral aspect of the proximal nailfold. Here we report a rare case of a 51-year-old man presenting with melanonychia mainly involving the distal nail plate. Histopathologic examination showed typical findings of onychomatricoma mainly involving the nail bed, while the nail matrix was largely uninvolved. We also identified fungal infection in a focal area of the distal nail plate. Our findings indicate that onychomatricoma can develop in the surrounding epithelial tissue of the nail unit, including the nail bed, and suggest that fungal infection may represent a secondary phenomenon of onychomatricoma. Keywords: fungus, nail bed, nail matrix, onychomatricoma Wang L, Gao T, Wang G. Nail bed onychomatricoma. J Cutan Pathol 2014; 41: 783–786. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Onychomatricoma is a rare tumor originating predominantly from the nail matrix.1 To date, only approximately 70 cases have been reported,2 most of them by Perrin et al.3 – 7 Onychomatricoma typically presents as longitudinal rough yellow bands and a thickened nail plate with splinter hemorrhages,1,3 or sometimes as a cutaneous horn3,8,9 or pterygium of the dorsal nail.5 Histopathologically, onychomatricoma is characterized by abnormal proliferation of basophilic epithelioid cells usually involving the nail matrix, accompanied by a thickened nail plate.1 – 7 In rare cases, the ventral aspect of the proximal nailfold has been reported to be involved.5 Herein, we present a rare case of onychomatricoma mainly involving the nail bed, which was associated with fungal infection of the abnormal nail plate. Report of a patient A 51-year-old man presented with a thickened black band in his left thumbnail. The lesion was asymptomatic and had enlarged gradually over the past 7 years. In the month prior to admission, the patient had experienced slight pain at the site of the lesion. Clinical examination showed a dark brown longitudinal band in the center
A
Lei Wang, Tianwen Gao and Gang Wang Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xian, China Gang Wang, MD, PhD and Tianwen Gao, MD, PhD Department of Dermatology Xijing Hospital Fourth Military Medical University No. 127 of Changlexi Rd Xian 710032 China Tel: +86 2984775401 Fax: +86 2984775401 e-mails: [email protected]; [email protected] Accepted for publication June 28, 2014
B
Fig. 1. A) A longitudinal black band mainly involving the distal nail plate was observed. B) Frontal view of the thickened and fragile distal nail plate.
of the nail (Fig. 1A). The nail plate became darker and thicker toward the distal part, and was splintered (Fig. 1B). Materials and methods The whole nail unit was removed for microscopic examination. The lesion was fixed in 10% buffered formalin for 24 h and subsequently
783
Wang et al. A
B
C
D
E
F
G
H
Fig. 2. A) Scanning magnification showing the whole nail unit. B) Low magnification showing that the nail matrix was largely uninvolved. C) High magnification showing a small cyst with several layers of basophilic cells and a prominent granular layer. D) Low magnification showing papilated proliferation of nail matrix cells and thickening of the nail plate. Infiltration of lymphocytes in the dermis was also observed. E) Intermediate magnification of the proximal nail bed showing V-shaped proliferation of basophilic cells, which translated into eosinophilic cells and then into a pink nail plate. F) Intermediate magnification of the distal nail bed showing similar histopathology. G) High magnification of the proximal nail bed showing the translation from matrix cells to nail plate. H) High magnification of the distal nail bed showing the translation from eosinophilic cells to nail plate.
in 10% ethylenediaminetetraacetic acid (EDTA) for 1 week of decalcification. The tissue was then embedded in a longitudinal direction, and the sections were stained with hematoxylin and eosin, and with periodic acid-Schiff (PAS) prior to examination.
784
Results The scanning magnification of the longitudinal appearance of the whole nail unit is shown in Fig. 2A. The proximal nail matrix and the proximal nail plate appeared normal (Fig. 2B), except for two small cystic structures located
Nail bed onychomatricoma A
B
C
D
Fig. 3. Schematic diagrams of (A) a normal nail unit; (B) onychomatricoma of the nail matrix5 ; (C) onychomatricoma of the nailfold5 ; and (D) onychomatricoma of the nail bed. Clinically, onychomatricoma can present as B, C, D, or a combination thereof (red: nail matrix; blue: nailfold and nail bed; beige: nail plate).
in the superficial dermis (Fig. 2C). There was papillomatous proliferation of basophilic epithelioid cells in the nail bed, and thickening of the distal nail plate (Fig. 2D), with the proximal nail bed showing a more prominent papillomatous appearance (Fig. 2E) than the distal part (Fig. 2F). In the proximal part of the nail bed, the proliferated basophilic cells transformed into eosinophilic cells, and then into a pink cornified nail plate (Fig. 2G). The histopathology of the distal part was similar to that of the proximal part of the nail bed, except that the papillomatous appearance of the epithelial cells was very subtle (Fig. 2H). In the dermis, there was no prominent fibroblast proliferation, and scattered lymphocyte infiltration was observed. Scattered blood serum was present in the abnormally thick nail plate (data not shown). In the distal nail plate adjacent to the hyponychium, we noticed fungal hyphae and spores in a focal area, which were more prominent upon Periodic Acid-Schiff staining. We also noticed hyphae and spores in a focal area of the stratum corneum of the hyponychium (data not shown). Discussion Onychomatricoma is recognized as a benign neoplasm originating from or differentiating toward nail matrix cells. Histopathologically, it usually involves the nail matrix, and may, in rare cases, involve the ventral aspect of proximal nailfold. The case presented herein shows
that onychomatricoma can develop from the nail bed; we believe that these results will help to increase our understanding of the histopathology of this rare disease. In our case, only the distal part of the nail plate was thickened, whereas the proximal nail plate appeared normal (Fig. 1). The clinical appearance was consistent with the microscopic findings, which showed a prominent papillomatous appearance of the nail bed, while the nail matrix was largely uninvolved. Perrin et al.5 reported onychomatricoma involving the nailfold near the nail matrix, which presented clinically as dorsal pterygium. According to their findings and our current observations, onychomatricoma can develop in both the nail matrix and the surrounding tissues, including both the ventral aspect of proximal nailfold and the nail bed (Fig. 3A–D). In this case, we found that the nail matrix was largely uninvolved, though two small cystic structures in the dermis under the normal nail matrix were noted. The cysts comprised basophilic cells at the periphery and a focal granular layer (Fig. 2C). It is unclear if this structure represented onychomatricoma at a very early stage. The proliferation of matrix cells in the nail bed and proximal nailfold may be caused by metaplasia.5 We propose that the inflammation in the dermis of our case may possibly lead to the metaplasia of nail bed cells. Others have suggested a role for fungal infection in the development of onychomatricoma, which has been detected by culture in a small number of cases.8,10 According to our results, the fungal infection was limited to a very focal area adjacent to the hyponychium; thus, we infer that the fungal infection was not a causative factor, but rather a secondary phenomenon of onychomatricoma. In the abnormal nail plate, we identified scattered blood serum, accounting for the black color of the lesion. This phenomenon has previously been described by Fayol et al.8 In conclusion, we have reported on a rare case of onychomatricoma of the nail bed associated with incidental fungal infection. Acknowledgements We would like to thank Dr Shi Yan for helping with the preparation of Fig. 3.
References 1. Baran R, Kint A. Onychomatrixoma: filamentous tufted tumour in the matrix of a
funnel-shaped nail: a new entity (report of three cases). Br J Dermatol 1992; 126: 510.
2. Cloetingh D, Helm KF, Ioffreda MD, Billingsley E, Rubin AI, Haneke E. JAAD
785
Wang et al. grand rounds quiz Onychomatricoma. J Am Acad Dermatol 2014; 70: 395. 3. Perrin C, Goettmann S, Baran R. Onychomatricoma: clinical and histopathologic findings in 12 cases. J Am Acad Dermatol 1998; 39: 560. 4. Perrin C, Baran R, Pisani A, Ortonne JP, Michiels JF. The onychomatricoma: additional histologic criteria and immunohistochemical study. Am J Dermatopathol 2002; 24: 199.
786
5. Perrin C, Baran R. Onychomatricoma with dorsal pterygium: pathogenic mechanisms in 3 cases. J Am Acad Dermatol 2008; 59: 990. 6. Perrin C, Baran R, Balaguer T, et al. Onychomatricoma: new clinical and histological features. A review of 19 tumors. Am J Dermatopathol 2010; 32: 1. 7. Perrin C, Langbein L, Schweizer J, et al. Onychomatricoma in the light of the microanatomy of the normal nail unit. Am J Dermatopathol 2011; 33: 131.
8. Fayol J, Baran R, Perrin C, Labrousse F. Onychomatricoma with misleading features. Acta Derm Venereol 2000; 80: 370. 9. Gaertner EM, Gordon M, Reed T. Onychomatricoma: case report of an unusual subungual tumor with literature review. J Cutan Pathol 2009; 36S1: 66. 10. Piraccini BM, Antonucci A, Rech G, Starace M, Misciali C, Tosti A. Onychomatricoma: first description in a child. Pediatr Dermatol 2007; 24: 46.
This document is a scanned copy of a printed document. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material.
