Sydney Ch'ng

Mast cells and cutaneous malignancies

This paper reviews the role of mast cells in the development and progression of basal cell carcinoma, squamous cell carcinoma and malignant melanoma. Mast cells accumulate around cutaneous malignancies. Current evidence suggests that mast cells contribute to the tumorigenesis of cutaneous malignancies through four mechanisms. (1) Immunosuppression: Ultraviolet-B radiation, the most important initiator of cutaneous malignancies, activates mast cells. Upon irradiation of the skin, trans-urocanic acid in the epidermis isomerizes to cis-urocanic acid, which stimulates neuropeptide release from neural c-fibers. These neuropeptides in turn trigger histamine secretion from mast cells, leading to suppression of the cellular immune system. (2) Angiogenesis: Mast cells are the major source of vascular endothelial growth factor in basal cell carcinoma and malignant melanoma. Vascular endothelial growth factor is one of the most potent angiogenic factors, which also induces leakage of other angiogenic factors across the endothelial cell wall into the matrix. Mast cell proteases reorganize the stroma to facilitate endothelial cell migration. As well, heparin, the dominant mast cell proteoglycan, assists in blood-borne metastasis. (3) Degradation of extracellular matrix: Through its own proteases, and indirectly via interaction with other cells, mast cells participate in degradation of the matrix, which is required for tumor spread. (4) Mitogenesis: Mast cell mediators including fibroblast growth factor-2 and interleukin-8 are mitogenic to melanoma cells. Current evidence supports an accessory role for mast cells in the development and progression of cutaneous malignancies. Emerging data, however, also suggest that mast cells might, in fact, have opposing roles in tumor biology, and the microenvironment could polarize mast cells to possess either promoting or inhibitory effects on tumors.

Relevance of the primary lesion in the prognosis of metastatic cutaneous squamous cell carcinoma.

It remains unclear how primary tumor factors impact on prognosis in patients with nodal metastasis in head and neck cutaneous squamous cell carcinoma (SCC). The purpose of this study was to assess whether primary tumor characteristics are independent prognostic factors.

Distant metastases from cutaneous squamous cell carcinoma—analysis of AJCC stage IV

The seventh edition of the American Joint Committee on Cancer (AJCC) Staging Manual introduced a more detailed system to stage regional lymph node metastases for disease with cutaneous squamous cell carcinoma (SCC). The purpose of this study was to determine if the inclusion of disease staged N2 and N3 together with disease staged M1 is an appropriate grouping within stage IV.

Osseointegrated implant-based dental rehabilitation in head and neck reconstruction patients

Dental restoration is an integral part of head and neck cancer reconstruction.

Concurrent primary and metastatic cutaneous head and neck squamous cell carcinoma: Analysis of prognostic factors

There is a small subgroup of patients with head and neck cutaneous squamous cell carcinoma (cSCC) in which nodal metastases present concurrently with the primary lesion. There is evidence that these tumors may represent a more aggressive subset of cSCC. The aim of this study was to determine whether alternative clinicopathologic prognostic factors should be applied to this patient cohort.

Reconstruction of the Trachea

This article reviews established methods of autologous tracheal reconstruction, the various synthetic prostheses that have been used in clinical practice, and briefly describes the latest developments in stem cell tracheal bioengineering and allogeneic tracheal transplantation. Reconstruction of the trachea is challenging due to its part cervical part thoracic location, proximity to major vessels, variable blood supply, and its constant colonization with bacteria. In cases of limited resection, primary anastomosis, autologous patch grafts, local advancement rotation flaps, and locoregional cutaneous and muscle flaps will often suffice. In more extensive resections, complex composite microsurgical reconstruction with a radial forearm free flap with cartilage grafts for skeletal support has proven to be viable and reliable. Synthetic tracheal prostheses, solid as well as porous, have been trialed with disappointing results. Infection, dislodgement, migration, and obstruction are not uncommon. Reconstruction with the cadaveric tracheal allografts and aortic allografts continue to be fraught with complications, specifically graft infections. Tracheal bioengineering and tracheal allotransplantation have emerged relatively recently. Despite early promising results, long-term outcome data on these new techniques are still lacking.

Options for configuring the scapular free flap in maxillary, mandibular, and calvarial reconstruction.

Background: A number of microvascular free-flap tissue transfer techniques exist for reconstruction of head and neck defects. The scapular free flap is a versatile option that can be used for a wide variety of defects in this complex region. Methods: A series of 42 free flaps from 41 patients was retrospectively identified from the senior author’s (Z.H.) database between 2006 and 2012. Information regarding patient demographics, indication for surgery, type of flap, reconstructive methods, complications, and prosthodontic outcome were reviewed and have been described. Result: A wide range of defects were reconstructed using the scapular free flap. Of the 42 reconstructions, 24 were for mandibular, 13 were for maxillary, and five were for calvarial reconstruction. The patients’ ages ranged from 28 to 82 years, with a median of 70 years. Dental restoration was achieved in eight patients with maxillary reconstruction and two patients with mandibular reconstruction. There were 11 major complications, including two total flap failures. Conclusions: The authors have found the scapular free flap to be a reliable, robust, and versatile flap that provides an unparalleled range of reconstructive options, with minimal donor-site morbidity. Thus, the authors believe that the scapular free flap is a valuable reconstructive option for patients with complex head and neck defects and in patients in whom comorbid disease contraindicates the use of the fibular free flap. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Factors predicting poor outcomes in T1N0 oral squamous cell carcinoma: indicators for treatment intensification.

This study investigated the impact of adverse pathological features (APFs) amongst patients with T1N0 oral squamous cell carcinoma (OSCC) on both tumour control and survival. We aimed to investigate clinicopathological factors that would predict poor outcomes and determine a clinically relevant threshold for the recommendation of additional treatment.

Relationship between postoperative complications and survival after free flap reconstruction for oral cavity squamous cell carcinoma

Current literature on the effect of postoperative complications on survival outcomes in head and neck cancers remains contradictory. This study assesses whether postoperative complications adversely affect survival in cases of complex surgical ablation and reconstruction of oral squamous cell carcinoma.

The scapular angle adds versatility to the latissimus dorsi free flap in complicated scalp reconstruction

The latissimus dorsi (LD) muscle has long been the flap of choice in reconstruction of extensive scalp defects. Its many attributes make it well suited for the role e a flat muscle of large surface area, a constant pedicle of good length and caliber, and negligible donor site morbidity. Scalp rotation flaps offer hair-bearing skin and are therefore superior in cosmesis, but their role is limited to nonirradiated small scalp defects. Although initially bulky and unsightly, the eventual aesthetics of an LD free flap following muscle atrophy and skin graft maturation is very acceptable. Based on the thoracodorsal vessels, the LD flap is one of many that can be raised on the subscapular system. The multiple independent pedicles of the subscapular/circumflex scapular and thoracodorsal axis allow harvest of various chimeric flaps, and freedom in orientation of the different components to tailor for the composite defects. As a result, the scapular and parascapular flaps, fasciocutaneous or osseocutaneous with the lateral scapular border, have often been a popular option in reconstruction of craniofacial deformities of hemifacial microsomia, Treacher Collins syndrome and Rhomberg disease. The ossecutaneous scapular flap is also commonly used for reconstruction of maxillary and mandibular defects following oncologic extirpative surgery. The LD and scapular angle osseomyogenous flap, on the contrary, is relatively little known, and has never been described for full-thickness scalp and calvarial reconstruction (Figure 1). We have used this chimeric flap option in four patients with a minimum follow-up period of 6 months, and have found the LD and scapular angle osseomyogenous flap to be highly reliable in the setting of complicated scalp and calvarial defects. The pathology were basal cell carcinoma (n Z 2), angiosarcoma and squamous cell carcinoma respectively. All were recurrent lesions previously treated with surgical resection and adjuvant radiotherapy. The