Comment
The diagnosis and management of PCC is difficult because the condition is uncommon (though its true incidence is unknown) and the presentation is nonspecific, invoking a wide differential diagnosis. In the literature, PCC presents as a slowly progressive, red-brown patch or plaque on the lower lip in older individuals.2,3,5,7 The lesion can progress to become eroded, ulcerated, fissured, or edematous.5
Differential Diagnosis
The clinical differential diagnosis of PCC is broad and includes inflammatory, infectious, and neoplastic causes, such as actinic cheilitis, allergic contact cheilitis, exfoliative cheilitis, granulomatous cheilitis, lichen planus, candidiasis, syphilis, and squamous cell carcinoma of the lip.7,9 The histologic differential diagnosis includes allergic contact cheilitis, secondary syphilis, actinic cheilitis, squamous cell carcinoma, cheilitis granulomatosa, and plasmacytoma.17-19
Histopathology
On biopsy, PCC usually is characterized by plasma cells in a bandlike pattern in the upper submucosa or even more diffusely throughout the submucosa.20 In earlier studies, polyclonality of plasma cells with kappa and lambda light chains has been demonstrated5; in this case, such polyclonality militated against a plasma cell dyscrasia. There have been reports of a various number of eosinophils in PCC,5,20 but eosinophils were not a prominent feature in our case.
Treatment
As reported in the literature, treatment of PCC has been attempted using a broad range of strategies; however, the optimal regimen has yet to be elucidated.15 Numerous therapies, including excision, radiation, electrocauterization, cryotherapy, steroids, systemic griseofulvin, topical fusidic acid, and topical calcineurin inhibitors, have yielded variable success.6,7,10-16
The success of topical corticosteroids, as demonstrated in our case, has been unpredictable; the reported response has ranged from complete resolution to failure.9 This variability is thought to be related to epithelial width and the degree of acanthosis, with ulcerative lesions demonstrating a superior response to topical corticosteroids.9
Conclusion
Our case highlights the challenges of diagnosing and managing PCC, especially through teledermatology. Initial photographs of the lesion (Figure 1) that were submitted demonstrated a nonspecific erosion, which was concerning for any of several infectious, inflammatory, and malignant causes. Prompt in-person evaluation was warranted; regrettably, the patient’s condition worsened rapidly in the 10 days it took for him to be seen in-person by dermatology.
Furthermore, this case necessitated 3 separate biopsies because the pathology on the first 2 biopsies initially was equivocal, demonstrating ulceration and granulation tissue. The diagnosis was finally made after a third biopsy was recommended by a dermatopathologist, who eventually identified a bandlike distribution of polyclonal plasma cells in the upper submucosa, consistent with a diagnosis of PCC. Our patient’s final disease presentation (Figure 3) was exuberant and may represent the end point of untreated PCC.