# Concurrent Basal Cell Carcinoma Masquerading As Osteomyelitis of the Acromioclavicular Joint: A Rare Presentation

## TL;DR

A rare case of basal cell carcinoma was mistaken for a bone infection, highlighting the need for thorough skin checks and timely medical care.

## Contribution

This paper presents a rare clinical case of infiltrative basal cell carcinoma misdiagnosed as osteomyelitis, emphasizing diagnostic challenges and management strategies.

## Key findings

- A 66-year-old man's non-healing wound was initially diagnosed as osteomyelitis but was later confirmed as infiltrative basal cell carcinoma.
- The case highlights the aggressive and subtle nature of infiltrative BCC, which can be difficult to diagnose without biopsy.
- Treatment involved antibiotics for suspected osteomyelitis and vismodegib for BCC, underscoring the need for comprehensive care.

## Abstract

Basal cell carcinoma (BCC) ranks as the most common form of skin cancer in the United States, and its prevalence continues to increase. Regular self-examinations of the skin can significantly enhance treatment outcomes. This report investigates a rare instance of BCC initially misdiagnosed as osteomyelitis, stemming from a longstanding wound on the patient’s left shoulder.

A 66-year-old male with a history of working in construction presented with a non-healing wound on his left shoulder, which he initially sustained from a metallic rod injury. Despite self-treatment, the wound deteriorated, revealing subcutaneous fat and producing foul-smelling drainage. Imaging suggested osteomyelitis, but the persistent and worsening nature of the wound over two years, previously concealed from his family and healthcare providers, prompted further investigation. A biopsy confirmed infiltrative BCC. The patient was referred to a tertiary care facility for comprehensive treatment, including long-term antibiotics for osteomyelitis and systemic therapy with vismodegib for BCC.

Basal cell carcinoma commonly appears as a pink or flesh-colored papule or nodule, often with surface features that aid in early identification and treatment. Yet, infiltrative BCC, like the case described here, can pose diagnostic challenges because of its subtle yet aggressive characteristics. The complex causes of BCC highlight the necessity of preventive actions, particularly for those with prolonged exposure to ultraviolet (UV) radiation. Treatment approaches primarily aim at removing the tumor and may incorporate targeted therapies for more advanced instances.

This case underscores the importance of regular skin self-examinations and prompt medical attention for lingering wounds, particularly among those at higher risk. Successfully addressing BCC demands a comprehensive strategy involving surgery, targeted chemotherapy, and preventive actions against potential future skin malignancies. Maintaining long-term surveillance is crucial for individuals with prior BCC diagnoses to detect any potential recurrence and address any enduring consequences of treatment.