Desmoplastic sebaceoma arising from nevus sebaceus: a new variant

Nevus sebaceus is known to have the potential to develop into various secondary tumors. We observed a sebaceoma arising from a nevus sebaceus excised from the left cheek of a 51‐year‐old woman. This sebaceoma showed desmoplastic change similar to that observed in desmoplastic trichoepithelioma and desmoplastic trichilemmoma. This heretofore undescribed desmoplastic variant of sebaceoma should not be mistaken for invasive sebaceous carcinoma.     

Subcutaneous desmoplastic small round-cell tumor: An unusual primary location expanding the differential of superficial round-cell tumors

Desmoplastic small round-cell tumor (DSRCT) is a rare, aggressive malignant tumor, which in the great majority of cases arises at abdominal-pelvic sites. Nevertheless, rare cases of primary extra-abdominal tumors have been reported. In challenging cases, its molecular hallmark, the EWSR1-WT1 reciprocal translocation, can be exploited diagnostically by various molecular techniques. Herein, we report an extremely rare case of primary subcutaneous DSRCT in an effort to raise awareness among our dermatopathology colleagues by expanding the differential of superficial round-cell tumors.     

Superficial dermal melanocytosis of the elderly: An exceptional occurrence?

The development of flat pigmented lesions on chronically sun-damaged (CSD) skin of the face may represent the clinical manifestation of a wide variety of hyperplastic/neoplastic melanocytic proliferations. We report the exceptional case of an acquired pigmented patch occurring on CSD skin, histopathologically characterized by diffuse hyperplasia of dendritic/spindled melanocytes in the superficial dermis within a widened band of actinic elastosis. This lesion was associated with a small focus of early invasive lentigo maligna melanoma (LMM). We show the melanocytic nature of the population of dermal pigmented cells by means of single and double immunohistochemical staining for melanocytic and histiocytic markers. The biologic significance of the focus of LMM within the hyperpigmented lesion (whether random collision phenomenon or causally related occurrence), as well as the pathogenesis of the whole dermal lesion are difficult to elucidate. Our case emphasizes the need for a better understanding of the pathophysiology of so-called dermal melanocytes.     

Updates on the multimodality management of desmoplastic small round cell tumor

Desmoplastic Small Round Cell Tumor (DSRCT) is a rare and an aggressive malignancy with poor outcome. This tumor can co-express epithelial, neural, and mesenchymal markers. The molecular hallmark of DSRCT is the EWS-WT1 fusion protein. Despite the diversities in treatment modality, the best results have been seen with radical surgery and adjuvant or neoadjuvant chemotherapy.     

Desmoplastic fibroblastoma (collagenous fibroma)

Desmoplastic fibroblastoma (DF) is a rare fibrotic tumor that has a wide anatomic distribution and it can appear in deep sections of the subcutis, in fascia, in aponeurosis or in skeletal muscles. This report describes a case of DF that appeared on the left side of the neck of a 55-year-old male as a 3.5-cm solitary, firm nodule. Histologically, it was composed of stellate or bland spindle-shaped cells embedded in a loose collagenous stroma. The entrapment of fat and muscle tissues was focally identified at the edges of the tumor. The stellate and multinucleated cells in the lesion were strongly positive for vimentin but negative for cytokeratin, smooth muscle actin, desmin, S-100, CD34, factor XIIIa, and CD68. These findings suggest that the stellate and multinucleated cells in the lesion were of fibroblastic origin and this neoplasm was pathologically benign.     

Dermal desmoplastic fibroblastoma presenting as a large sacral mass

Desmoplastic fibroblastoma (collagenous fibroma) is a rare and recently recognised benign tumour. Most desmoplastic fibroblastomas arise in the subcutaneous tissue or skeletal muscle. Involvement of the dermis is extremely rare. We describe an unusual case of dermal desmoplastic fibroblastoma presenting as a large sacral mass in a 16‐year‐old male. An awareness of this entity is necessary to avoid confusion with other benign and malignant soft tissue neoplasms.     

Desmoplastic fibroma of the ulna bone

A fibroma is a benign tumour composed of fibrous connective tissue and they can grow in all organs. They can be classified based on consistency into hard or soft fibroma, based on histological characteristics into desmoplastic, chondromyxoid, ossifying, non-ossifying fibroma. They can also be classified based on tissue of origin or location in the body, it can also be classified into superficial or deep fibroma. This is a report of a 15-year-old Nigerian boy with a recurrent left ulnar tumour which was rapidly growing and has been excised three times. Preoperative investigations, i.e., plain radiograph, full blood count and fine needle aspiration cytology were done. Patient could not afford CT scan which was requested for. First excision was in 2009. Recurred within 1 year and had a repeat excision in 2011. He had a second recurrence 9 months after and had to have another excision. The last tumour excision left only the part of the left ulna that forms the proximal radioulnar joint and elbow joint. Patient has been followed up after the last excision for 18 months with no recurrence.     

Intra-Abdominal Desmoplastic Small Round Cell Tumor in Children: A Clinicopathologic Study

Desmoplastic small round cell tumor (RCT) is a relatively newly recognized neoplasm. It has a very distinct morphologic and high-grade polyphenotypic expression with a very poor prognosis. It is commonly seen in adolescent boys. We describe two cases of intra-abdominal desmoplastic small RCT in young girls (5 and 11 years of age). In both cases, the exact origin of tumor in the abdomen could not be established. Histopathologic examination of the biopsy specimens showed distinct desmoplastic stroma and coexpression of various epithelial, neural, and muscle markers. These two patients were treated primarily by debulking surgery followed by adjuvant chemotherapy (RCT II protocol). One of the two had a stable disease while the other had a progressive disease while on treatment. Thus our findings support the diverse histogenesis of this tumor and its poor prognosis.     

Paratesticular desmoplastic small round cell tumors: A case report and review of the literature

Desmoplastic small round cell tumor (DSCRT) is a rare malignancy most often seen in the abdomen or pelvis of young men. Unfortunately, this disease is usually metastatic at diagnosis and has dismal outcomes. We describe a case of isolated paratesticular DSCRT in a 14‐year‐old male successfully treated with surgical resection, chemotherapy, and adjuvant radiation, and we present a review of the relevant literature. It appears that isolated, paratesticular DSCRTs have a markedly better outcome than the classic abdominal or pelvic location. We hypothesize that this is due to earlier detection and the relative ease of surgical resection.