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Subungual Mass in a Middle-aged Woman

Educational Objective
Based on this clinical scenario and the accompanying image, understand how to arrive at a correct diagnosis.
1 Credit CME

A 54-year-old woman presented with a 7-year history of a painful subungual mass of the right thumb. The lesion was initially believed to be an infection; however, results of both mycological and bacteriologic examinations were unremarkable. The patient had no notable medical history, including dyskeratosis congenita, trauma, sun exposure, radiation exposure, chemical exposure to tar or arsenic or exposure to minerals, chronic immunosuppression, or chronic infection. Physical examination revealed a subungual nodule with some exudation and crusts. The distal nail plate had been destroyed and showed onycholysis with obvious separation from the nail bed (Figure, A). Pertinent laboratory results (complete blood cell count, liver panel, kidney panel) were within normal limits. Lesional biopsy was also performed (Figure, B and C).

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B. Subungual squamous cell carcinoma

Malignant subungual tumors are rare and are associated with subungual squamous cell carcinoma (SCC), Bowen disease, melanoma, basal cell carcinoma, and subungual keratoacanthoma among others. Of these malignant neoplasms, subungual SCC is the most frequent.14 Subungual SCC has been considered a low-grade malignant neoplasm with a good prognosis compared with SCC arising elsewhere.24 About 20% of patients with subungual SCC have bony invasion, and metastasis and lymph node involvement is uncommon.14 Usually, the patients tend to be men aged 50 to 79 years, and typically, a single digit, especially the thumb or hallux, is likely to be involved.13

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Article Information

Corresponding Author: Jun Li, MD, Department of Dermatology, Peking Union Medical College Hospital, No. 1 Shuaifuyuan Wangfujing, Dongcheng District, Beijing 100730, China (lijun35@hotmail.com).

Published Online: October 31, 2019. doi:10.1001/jamaoncol.2019.4500

Conflict of Interest Disclosures: Drs Gong and Li reported support by the National Key Research and Development Program of China (No. 2016YFC0901500).

Additional Contributions: We thank the patient for granting permission to publish this information.

References
1.
Patel  PP, Hoppe  IC, Bell  WR, Lambert  WC, Fleegler  EJ.  Perils of diagnosis and detection of subungual squamous cell carcinoma.  Ann Dermatol. 2011;23(suppl 3):S285-S287. doi:10.5021/ad.2011.23.S3.S285PubMedGoogle ScholarCrossref
2.
Kelly  KJ, Kalani  AD, Storrs  S,  et al.  Subungual squamous cell carcinoma of the toe: working toward a standardized therapeutic approach.  J Surg Educ. 2008;65(4):297-301. doi:10.1016/j.jsurg.2008.05.013PubMedGoogle ScholarCrossref
3.
Batalla  A, Feal  C, Rosón  E, Posada  C.  Subungual squamous cell carcinoma: a case series.  Indian J Dermatol. 2014;59(4):352-354. doi:10.4103/0019-5154.135480PubMedGoogle ScholarCrossref
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Meesiri  S.  Subungual squamous cell carcinoma masquerading as chronic common infection.  J Med Assoc Thai. 2010;93(2):248-251.PubMedGoogle Scholar
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Wong  KY, Ching  DL, Gateley  D.  Subungual squamous cell carcinoma.  BMJ Case Rep. 2015;2015:bcr2014207565. doi:10.1136/bcr-2014-207565PubMedGoogle Scholar
6.
Gatica-Torres  M, Arguello-Guerra  L, Manuel Ruiz-Matta  J, Dominguez-Cherit  J.  Subungual pigmented squamous cell carcinoma presenting as a grey longitudinal melanonychia in a young patient.  BMJ Case Rep. 2016;2016:bcr2016215390.PubMedGoogle Scholar
7.
González-Rodríguez  AJ, Gutiérrez-Paredes  EM, Montesinos-Villaescusa  E, Burgués Gasión  O, Jordá-Cuevas  E.  Subungual keratoacanthoma: the importance of distinguishing it from subungual squamous cell carcinoma  [in Spanish].  Actas Dermosifiliogr. 2012;103(6):549-551.PubMedGoogle ScholarCrossref
8.
Zaraa  I, Cogrel  O.  Images in clinical medicine. subungual tumor of the thumb.  N Engl J Med. 2012;367(23):2240. doi:10.1056/NEJMicm1104277PubMedGoogle ScholarCrossref
9.
Campanelli  A, Borradori  L.  Images in clinical medicine. subungual exostosis.  N Engl J Med. 2008;359(25):e31. doi:10.1056/NEJMicm074461PubMedGoogle Scholar
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