1. A 54-year-old Colombian man presents with nail dystrophy of two years’ duration. Physical exam reveals longitudinally banded thickening of the lateral half of the nail plate with yellowish brown discoloration, transverse overcurvature of the nail, longitudinal white lines, and splinter hemorrhages.
Diagnosis: The lesion, diagnosed as onychomatricoma was surgically removed and sent for histopathologic study. Onychomatricoma is a subungual tumor characterized by banded or diffuse thickening, yellowish discoloration, splinter hemorrhages, and transverse overcurvature of the nail plate. Because the condition is not well known, it is often misdiagnosed.
For more information, see “ Onychomatricoma: An Often Misdiagnosed Tumor of the Nails .” Cutis. 2015;96(2):121-124.
2. A 21-year-old woman has a slow-growing, asymptomatic nodule on the great toe. She denies antecedent trauma. A firm, flesh-colored, semimobile, nontender, subungual nodule can be seen in the distal lateral nail bed, extending into the adjacent tissue. Radiographic exam shows focal calcification of the nodule, with direct communication to the underlying distal phalanx.
Diagnosis: Subungual exostosis is a relatively uncommon, benign, osteocartilaginous tumor arising from the distal phalanx beneath the nail. It typically appears on the great toe during the second to third decade of life and has an equal incidence in both sexes. Its similarities to other dermatologic disorders involving the nail bed can lead to misdiagnosis, which may result in inadequate or extreme treatment.
For more information, see “ Subungual Exostosis .” Cutis. 2012;90(5):241-243.
3. For the past year, a 30-year-old man’s left great toe has had a 3-cm exophytic, yellowish red, subungual nodule that is obliterating the nail plate. Ten years ago, a similar nodule in the same location was removed via laser by a podiatrist. Plain radiographs demonstrate an inferior cortical lucency of the distal phalanx, as well as a lucency over the nail bed with calcification extending to the soft tissues. MRI reveals bone erosion from the overlying mass.
Diagnosis: Digital fibromyxoma is the term used to describe a distinctive, slow-growing, soft-tissue tumor with a predilection for the periungual or subungual regions of the fingers and toes. This benign growth typically presents as a painless or tender nodule in middle-aged adults, with a slight male predominance. In a case series of 124 patients, 36% who had imaging studies showed bone involvement by an erosive or lytic lesion. Soft-tissue invasion of the bone is demonstrated by scalloping on plain radiographs.
For more information, see “ Toe Nodule Obliterating the Nail Bed .” Cutis. 2016;97(4):260, 281-282.
4. A 41-year-old man presents with a slowly growing, tender lesion located on the left great hallux. When it first appeared five months ago, it resembled a blister. On exam today, a firm, 3.5-cm, flesh-colored, pedunculated nodule is seen on the lateral aspect of the toe. No lymphadenopathy is found. The patient reports no history of keloids or trauma to the foot.
Diagnosis: Shave biopsy showed findings consistent with dermatofibrosarcoma protuberans. A chest radiograph was unremarkable. Re-excision was performed with negative margins on frozen section but with positive peripheral and deep margins on permanent sections. The patient subsequently underwent amputation of the left great toe and was lost to follow-up after the initial postoperative period.