Apocrine hydroadenoma mimicking a Morton's neuroma: a rare differential diagnosis.

A 62-year-old woman, with neuropathic pain and paresthesia in her right forefoot, showed a circumscribed soft tissue swelling on the sole between the second and third metatarsal. Ultrasound (US) imaging showed a well-defined lesion in the second intermetatarsal space, without vascularization sign at Power Doppler (PD). In the first hypothesis, these findings led to Morton's neuroma. Magnetic Resonance Imaging (MRI), demonstrated a dumbbell-shaped lesion between the II and the III metatarsal heads; it extended cranially to the subcutaneous fat of the dorsal slope. The MRI findings weren't compatible with a classic Morton's neuroma and were radiologically undetectable. The patient had a sub-total excisional biopsy. The anatomopathological features were specific to an apocrine hydroadenoma from an ectopic sweat gland. This rare pathology has not been previously described in the literature and it must be considered as a differential diagnosis due to the clinical presentation and the US appearance mimicking Morton's neuroma.

Solitary fibrous tumor occurring at unusual sites: A clinico-pathological series of 31 cases with emphasis on its wide morphological spectrum.

Solitary fibrous tumor (SFT) is a relatively rare mesenchymal fibroblastic tumor occurring most commonly in adults with no gender predilection. Although the pathological diagnosis of SFT is usually straightforward, some difficulties may occasionally arise mainly due to the wide morphological spectrum exhibited by this tumor. In the present paper we aimed to evaluate the unusual clinicopathological features in a series of 31 SFTs arising from parenchymal organs, superficial soft tissues and deep soft tissues. Our results emphasize that SFTs may occur anywhere, including unusual sites such as periosteum of the thoracic spine, mesorectal tissue, hepatic hilum, paravescial space, kidney and breast. Moreover, a wide morphological spectrum was observed in tumors included in our series. The most striking morphological features observed included: extensive lipomatous component, myxoid stromal changes, epithelioid cell component, metaplastic mature bone, neurofibroma-like, myxofibrosarcoma-like and pseudoalveolar-like areas. Additionally, multinucleated giant cells and sarcomatous dedifferentiation were also identified. Our paper emphasizes that SFT may occur in unusual anatomical locations and exhibits a wide morphological spectrum. Pathologists must be aware of these features to avoid confusion with other benign and malignant neoplasms that may show overlapping morphological features.