Complex regional pain syndrome as a paraneoplastic disorder associated with metatypical basal cell carcinoma.

Metatypical basal cell carcinoma (MTBCC) is a rare form of tumor, which associates the clinical and histopathological (HP) characteristics of both basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), with a 5% chance for the development of metastases. The reference diagnosis remains the HP confirmation from the lesional tissue. The current report illustrates the case of a 74-year-old patient, diagnosed with MTBCC consequently to the biopsy from the clinically malignant lesion with HP and immunohistochemical examination, currently in clinical remission following surgical treatment. The musculoskeletal symptoms represent the patient's admission reason to the Clinic of Rheumatology, where he was diagnosed with paraneoplastic type I complex regional pain syndrome (CRPS-I). The onset was six weeks prior with intense pain in the upper limb, burning sensation and nondermatomal distribution, exacerbated by lowering the position of the upper limb. The clinical evaluation revealed vasomotor disorders: color changes on the skin of the upper limb, venous turgescence on the back of the hands, and local increased temperature. Also, there were evident sudomotor modifications with hyperspiration and fluffy edema. The presence of clinical manifestations associated with the HP confirmation of MTBCC and the information provided by the imaging tests regarding the evaluation of tumor extension advocates for the diagnosis of paraneoplastic CRPS, consequently to both the primary tumor and the pulmonary metastasis. Diagnosis of CRPS-I is generally established on the basis of clinical criteria after excluding other conditions that may explain the degree of pain and the existing dysfunction. The therapist should be aware of the clinical manifestation of CRPS, as early recognition and aggressive treatment often leads to the best response.