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  Table of Contents    
CASE REPORT  
Year : 2016  |  Volume : 59  |  Issue : 2  |  Page : 232-234
Necrotizing sialometaplasia: Manifestation of a localized unclassified vasculitis


1 Department of Pathology and Lab Medicine, All Institute of Medical Sciences, New Delhi, India
2 Department of Gastroenterology, AMRI Hospital, Bhubaneswar, Odisha, India
3 Department of Otorhinolaryngology, All Institute of Medical Sciences, New Delhi, India

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Date of Web Publication9-May-2016
 

   Abstract 

Necrotizing sialometaplasia is a rare benign and self-limiting disease, which commonly affects the minor salivary glands. Typically, it involves the seromucinous glands located at palate, buccal mucosa, tongue, tonsil, nasal cavity, trachea, larynx, maxillary sinus, and retromolar trigone. We report two such cases of necrotizing sialometaplasia to create awareness among the pathologists and surgeons because of its close morphological and clinical resemblance to squamous cell carcinoma. We have also documented that, the ischemic necrosis of salivary gland is the result of a vasculitic process.

Keywords: Ischemic necrosis, minor salivary glands, necrotizing sialometaplasia, tumor like lesion, vasculitis

How to cite this article:
Senapati S, Samal SC, Kumar R, Patra S. Necrotizing sialometaplasia: Manifestation of a localized unclassified vasculitis. Indian J Pathol Microbiol 2016;59:232-4

How to cite this URL:
Senapati S, Samal SC, Kumar R, Patra S. Necrotizing sialometaplasia: Manifestation of a localized unclassified vasculitis. Indian J Pathol Microbiol [serial online] 2016 [cited 2019 Dec 12];59:232-4. Available from: http://www.ijpmonline.org/text.asp?2016/59/2/232/182018



   Introduction Top


Necrotizing sialometaplasia (NSM) is defined as a reactive necrotizing inflammatory process involving the minor salivary glands.[1],[2] There are lobular infarction, necrosis and concurrent squamous metaplasia of ducts, and acini of salivary glands. Though minor salivary glands are frequently involved, major salivary glands are also affected less often.[3] The pathogenesis of disease is still not clear but it is believed to be predominantly of ischemic origin. Causes of ischemia are not clear. Present cases of concern showed active and healed vasculitis away from lesional site causing impairment of circulation, which is not been described by previous investigators. Conservative management is the treatment of choice. We present two such cases of NSM with a brief review of literature.


   Case Reports Top


Case-1

A 53-year-old male presented to the otorhinolaryngology outpatient department with the chief complaint of ulceration over the anterior part of the hard palate for 3 months duration without any associated pain. The ulcer was initially localized to the hard palate, and subsequently ulceration was also noted over the vestibule of the nose and in the process he lost two of his upper incisor teeth [Figure 1]a and [Figure 1]b. The patient had several consultations and advised series of antibiotics but without any further improvement. He was a known case of diabetes mellitus for last 12 years and been on insulin therapy. Considering the nonhealing nature of the ulcer, a biopsy was taken from the edge of the ulcer and sent for histopathological examination. The differential diagnosis offered by the clinician were Fungal cellulitis, mid line Wegener granulomatosis, tuberculoma and malignancy. He had recovered completely with the healing of ulcers both on the nasolabial fold and hard palate within a period of 6 weeks with conservative management and lost to follow-up subsequently.
Figure 1: (a and b) Ulcer in the nasolabial fold and hard palate (case-1). (c and d) Lesion before debridement and complete healing after 3 months (case-2)

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Case-2

A 62-year-old male presented to otorhinolaryngology outpatient department with a progressively ulcerated lesion on the anterior one-third of the tongue associated with burning sensation and shooting pain, which was referred to the right ear. He also had excessive salivation, not able to drink or eat, and difficulty in speaking for 3 weeks. His general physical examination and laboratory investigations including ANCA were within normal limits. However, the patient was admitted to the respective inpatient department with a provisional diagnosis of squamous cell carcinoma. As the anterior, one-third of the tongue was necrosed [Figure 1]c, a debridement surgery was done. Slough was removed, and incisional biopsy was taken from the viable area, which was sent for histopathological examination. The following debridement there was a complete loss of speech. However, the patient was discharged on the 5th day of surgery, and was on regular follow-up. Review after 3 months revealed complete healing of the lesion with cessation of salivation and return of speech [Figure 1]d.

Histopathology

Biopsies were processed. Histopathological examination in both the cases revealed ischemic necrosis of ductular and acinar epithelium with marked squamous metaplasia [Figure 2]a. However, the normal lobular configuration and contour of salivary gland acini were well preserved. Mild to the moderate inflammatory infiltrate composed of lymphocytes, plasma cells, neutrophils, and histiocytes were present in the stroma. Morphological evidence of ischemic pathology in the form of intravascular thrombus in case-2 and microangiopathy with organized thrombus in case-1 were noted. In case-2 sections from the slough showed myonecrosis of skeletal muscle with heavy microbial colonization probably by the oral commensals. The special stain did not demonstrate any fungus or acid-fast bacilli. A histopathological diagnosis of NSM was made. Both the cases showed complete healing of the lesion with conservative management.
Figure 2: (a) Infarction of salivary glands acini (H and E, ×100).

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Ischemic necrosis of salivary gland acini replaced by metaplastic squamous epithelium was the main morphological finding in both the cases. The sequences of changes noted are pure infarction of acini with intact basement membrane to metaplastic change and background inflammation of variable degree. The inflammatory cells consist predominantly of plasma cells, and few lymphocytes were noted in case-1 [Figure 2]b.

Endothelial injury with adhesion and undermining by neutrophils leading to lifting and denudation of endothelial cells were noted [Figure 2]c. Focal transmural inflammation and segmental fibrinoid necrosis of the vessel wall with thrombus formation in some of them leading to luminal narrowing and occlusion were also seen [Figure 2]d. Muscular arterioles with perivascular and mural inflammation and collagenisation were found [Figure 3]a and [Figure 3]b. Characteristic of healed vasculitis such as myointimal thickening, disorganization, and damage of internal elastic lamina resulting in luminal occlusion were noted [Figure 3]c and [Figure 3]d.
Figure 3: (a) Vessels with inflammation in and around vessel wall with organized thrombus and recanalization (H and E, ×200).

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Immunohistochemical study revealed expression of p53 in the residual and metaplastic epithelial cells. Proliferative index (MiB-1) of these cells was around 20–30%

[Figure 3]e and [Figure 3]f.


   Discussion Top


A biopsy of suspected NSM should be adequate and representative to avoid sampling of only necrotic material.[4] As in case-2, where the area of necrosis is extensive leading to slough formation, surgical debridement of the lesion considered to be necessary, and the biopsy was taken from the viable end to get a representative sample. Histopathology plays a key role in making a conclusive diagnosis of NSM.[5] Bland appearing morphology of metaplastic squamous cells, the absence of cellular atypia, and preservation of lobular morphology are the three cardinal features based on, which the diagnosis of NSM is made.[6] Expression of p53 indicates hypoxic stress to epithelial cells secondary to ischemia.[7] Increased proliferative index is probably because of regenerative activity. Therefore, Immunohistochemical studies of these two markers are not helpful in ruling out malignancy in this scenario.

The etiology and pathogenesis of this condition are poorly understood, but it is strongly believed to be predominantly due to compromise in the vascular supply to salivary gland lobules.[8],[5] The vascular changes observed in our cases are early active vasculitis to healed lesions resulting in scarring of the vessel wall, which are away from the site of necrosis. The microscopic evidence of ischemia noted here are in the form of microangiopathy, hyperplastic arteriosclerosis and necrotizing arteriolitis with thrombus formation.

Hyaline arteriosclerosis of small vessels are commonly seen in older patients without hypertension.[9] Microangiopathy is also described in nondiabetic and normotensive elderly individuals but rarely to the extent as seen in long standing diabetes.[9] Active vasculitis with mural necrosis and subsequent thrombus formation have no relation with diabetes, hypertension, or aging. The causes of active vasculitis in this scenario, whether due to immune mediated as there are a lot of plasma cells in the background in case-1 or due to antigenic cross-reactivity of vessel wall with bacterial antigen derived from oral commensals, needs further study.

A high index of awareness about this entity should be there among pathologists and in the same context operating surgeons should respect the pathologist's opinion so that unnecessary mutilating surgery can be avoided. The causes of localized vasculitis resulting in infarct of the glands need to be established in a larger prospective study with complete collagen profile, HLA haplotype, and immunofluorescence technique.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
   References Top

1.
Abrams AM, Melrose RJ, Howell FV. Necrotizing sialometaplasia. A disease simulating malignancy. Cancer 1973;32:130-5.  Back to cited text no. 1
    
2.
Brannon RB, Fowler CB, Hartman KS. Necrotizing sialometaplasia. A clinicopathologic study of sixty-nine cases and review of the literature. Oral Surg Oral Med Oral Pathol 1991;72:317-25.  Back to cited text no. 2
    
3.
Farina D, Gavazzi E, Avigo C, Borghesi A, Maroldi R. Case report. MRI findings of necrotizing sialometaplasia. Br J Radiol 2008;81:e173-5.  Back to cited text no. 3
    
4.
Kaplan I, Alterman M, Kleinman S, Reiser V, Shuster A, Dagan Y, et al. The clinical, histologic, and treatment spectrum in necrotizing sialometaplasia. Oral Surg Oral Med Oral Pathol Oral Radiol 2012;114:577-85.  Back to cited text no. 4
    
5.
Randhawa T, Varghese I, Shameena P, Sudha S, Nair RG. Necrotizing sialometaplasia of tongue. J Oral Maxillofac Pathol 2009;13:35-7.  Back to cited text no. 5
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6.
Carlson DL. Necrotizing sialometaplasia: A practical approach to the diagnosis. Arch Pathol Lab Med 2009;133:692-8.  Back to cited text no. 6
    
7.
Kumar V, Abbas AK, Aster JC. Neoplasia. In: Kumar V, editor. Pathologic Basis of Disease. 9th ed. New Delhi: Reed Elsevier India Private Limited; 2014. p. 265-340.  Back to cited text no. 7
    
8.
Rye LA, Calhoun NR, Redman RS. Necrotizing sialometaplasia in a patient with Buerger's disease and Raynaud's phenomenon. Oral Surg Oral Med Oral Pathol 1980;49:233-6.  Back to cited text no. 8
    
9.
Mitchell RN, Schoen FJ. Blood vessels. In: Kumar V, editor. Pathologic Basis of Disease. 8th ed. New Delhi: Reed Elsevier India Private Limited; 2012. p. 487-528.  Back to cited text no. 9
    

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Correspondence Address:
Susama Patra
Department of Pathology and Lab Medicine, All India Institute of Medical Sciences, Bhubaneswar - 751 019, Odisha
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0377-4929.182018

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    Figures

  [Figure 1], [Figure 2], [Figure 3]

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