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Pathologic interpretation of x-ray findings
Department of Oral Surgery Edited by ROBERT
H. Ivy
AND KURT
H.
THOMA
Articles on oral surgery, radiography, and anesthesia should be submitted to Dr. Robert H. Ivy, 1930 Chestnut St., Philadelphia, Pa, Articles on oral pathology should be submitted to Dr. Kurt H. Thoma, 47 Bay State Road, Boston, Mass.
PATHOLOGIC INTERPRETATION OF X-RAY FINDINGS* KURT
H.
THOMA, D.M.D., BOS'l'ON, MASS.
E HAVE arrived at a time in the development of our profession when proper recognition is given to the value of the sciences in the art of practicing dentistry. The reason is quite evident-dental and oral diseases which heretofore were thought to be of purely local origin have been shown to come from metabolic disturbances, blood dyscrasias, and other systemic diseases. In order to treat such conditions successfully one must assume a different attitude from that taken only a few years ago. This especially applies to the science of recognizing disease-diagnosis. Diagnosis today is, in very few dental schools, treated as a separate subject; it is talked about in various courses, but like a fata morgana it is never within practical reach and never taught systematically. It involves a wide knowledge and experience; the diagnostician must be able to interpret laboratory analyses of saliva, blood, and urine, bacteriologic tests, and pathologic roports , he must be able to read roentgen films; and he must have a clear mental picture of the tissue changes brought about by disease-pathology. All methods of examination are important and may be needed before a diagnosis can be made. One alone should not be relied upon, and this applies particularly to the now so popular roentgen examination. Although it is indisputably one of the most valuable means of detecting abnormalities of the teeth and jaws, it should not be regarded as complete and final. Unfortunately, the ordinary roentgenologist makes not even a pretense of studying the symptoms and history of the patient; he only takes x-ray pictures, and from their disclosure he writes a report. Such a report is not a diagnosis, and it is to be regretted that roentgen examination has become a specialty in its own right. It is only an aid, a tool, one of the several tests that should be at the disposal of the diagnostician, but not accessible to the patient, as it is today through commercial x-ray laboratories. Not only must roentgen findings be interpreted on a pathologic basis, but x-ray examination should also have a prominent place in the study of pathology. In the past we have employed the microscope alone in the laboratory, but there is no reason why the roentgen method should not be used as well. The roentgen examination shows the gross involvement of the teeth and jaws best and also the extent to which the pathology has progressed. Generally
W
"Read before the Pennsylvania State and Philadelphia County Dental Societies, February 0. 1936.
383
384
Kurt H. Thorna
it furnishes indications as to the character of the lesion, whether its effect is localized or diffuse, osteolytic or osteoblastic, odontolytie or odontoblastic; whether it is encapsulated, encysted, expanding, infiltrating, or perforating the bone. The x-ray picture therefore does not indicate specific disease but shows the result of the disease, or its effect on the bone and dental structures. The microscopic study, on the other hand, gives a clear picture of the actual tissue changes in disease, demonstrating the nature of the lesion and the systemic reaction caused by it. With the microscope we can visualize what is actually going on, and the greater our power to visualize the pathologic processes the better is our concept of disease. To demonstrate how uncertain and vague the findings by the x-ray method can be, it is only necessary to examine an unusual lesion. This will prove at once that pathologic interpretation is an absolute necessity. Study, for example, the x-ray picture shown in Fig. 1 and ask yourself the question: What is actu-
Fig. l.-Mandibular second molar of a boy ag'ed twelve years. Tooth presented a defective occlusal fissure. Exploration caused hemorrhage. Roentgen examination shows a radiolucent central defect. Pathologic examination is necessary to make a diagnosis.
ally going on in the tooth which shows the central radiolucent area? The answer can be given only by histologic examination. The need for keen pathologic thinking is also demonstrated when using a roentgen picture for the diagnosis of pulp disease. We know that the pulp itself is not visible except for calcareous deposits; therefore secondary evidence must be relied upon to obtain the desired information. An enlargement of the periapical space presents such evidence, as it indicates an inflammatory reaction caused by the infected pulp. The finding of an etiologic factor, such as deep primary or secondary caries, or a parodontal pocket reaching close to the apex, signifies, especially if associated with symptoms, that an infection may have traveled either from the cavity via the pulp to the periapical tissue (descending pulpitis) or from the parodontal pocket to the apex and into the root canal (ascending pulpitis). When bone is involved by disease, the x-ray examination helps first of all to determine whether the effect is of an osteoblastic or osteolytic nature.
Pathologic I nt erp retation of X-ray Findings
385
The osteoblasti c reaction causes new for mation of bone. Thi s may be inside the jaw (enostosis, sclerosis of th e spongiosa, central osteogenic t umor) or outs ide of the jaw (exostosis, torus palatinus and man dibul are, osteogenic tumol's ). In some cases it may be found both inside and outside the bone, as is the case in osteogenic sarcoma. Th e det erm inati on of the actu al pat hologic process, tlie question whet her t he condition is of infectious, tuberc ulous, syphiliti c, or neopla stic na ture, r equires microscopic study . The oste olytic r eact ion causes resorption of bone. The evaluation of the defects caused by this process is mor e difficult sti ll. The lesions may form an are a with an osteitic margin. Thi s means th at there is a gradual chan ge from th e diseased to th e normal without definite demar cat ion. It is characteristi c of infectious resorption, but it may also be caused by an infiltrating tumor (benign giant -cell tumor, carcinoma, and other malignant tumors ). A cystic area has a well-defined, radiopaque margin due to incasement of the lesion by a corti cal
Fig. 2.- Pho t og r a ph of a n . exc ised m a nd ible with s u b maxtll arv g la nds a ttached. of carc in o ma of the lip meta sta s iz in g t o the j a w.
From a case
layer of bone. This condition is seen in all t ypes of odontogenic and fissural cyst s, but may also be encountered in the case of encapsulat ed central tumors (adamantinoma, fibroma ) . Any odontogenic connect ion may favor classification as a follicular or radi cular cyst, while multiple occurrence and trabeculation ind icate neoplastic disease. It must be rememb er ed, however, that f rom all kinds of odonto geni c cysts ada mantinoma or carcinoma may develop wit hout showing th e change in th e roentgen picture at first. Later notching at th e margin or per fora ti on and extension into the neighboring tissue result, and indicat e definite local mali gnancy. 'I'h e so-called punched-out area is left for consideration. It is a well-defined shadow with a definit e mar gin but no cort ical bone sur rounding it. 'When it is seen in dental x-ray pi ctu r es, it is ofte n looked at as a much more ser ious in fect ion than is r epresented by th e indefinite r adiolucent area with osteitic margin . This br in gs out clearl y th e fallacy of r eading x-ra y pictures without a background of pathology. Th e punched-out area means very littl e pathol ogically ; it has to do with t he anatomic involvement of t he bone. It
386
/lu rt 11. T honui
indicates perforation of th e thick, dense, and t herefo re r adi opaque cort ex of t he jaw, and may be caused by denta l in fection as well as t umors, espec ially multiple myeloma which also forms such defects in other bones, especially the r ibs, calvaria, and jaws. All th is t eaches t hat t he x-r ay is a valuable aid to show the presen ce of disease, and that it is useful to disclose th e exte nt of in volvement of th e t eeth and jaws, but t hat it does not give sufficient evidence to make a final diagnosis, Lon g continued comp arative study of jaw lesions by mean s of the x-ray examination and th e microscope is necessary t o in cr ease our diagn osti c knowl edge. This can be accomplished first by sup plying the student with a roentgen film of ever y case he studies wit h t he microscope, and second by examining excised specimens by means of th e x-ray before making th e hist ologic preparations. The value of such a procedu re is app reciat ed when we comp are the photograph of an excised mandible of a case of carcinoma of th e lip ( F ig. 2) with the x-ray of th e specimen showing t he actual involvement of th e bone by metastasis, as seen in Fig. 3.
F ig , 3.- X-r a y p ictur e of t h e s pecime n in Fig. 2 s h owin g osteo lytic d efec t in b od y o f the m and ibl e, d ue t o t h e m etastatic n ew f orm a t io n .
By cont inued comparison with the actual path ologic p rocesses the interp retati on of the various roent gen signs will become more and more accurate. W e have already learned th at t umor s which are either in side or outside the cortex are generall y benign, while those which are both inside and out arc liable to be mali gnant. W e r ecogni ze an indefinit e, so-call ed ost eit ic margin with exte nsions away from th e main defect t o mean spreadin g in t o th e adjacent bone t hroug h infiltrati on. \Ve kn ow that cer tain jaw lesions may be part of a gener alized disease, such as hyperparath yroidi sm, xa nthomatosis, Paget's disease, acromegaly, generalized ost eomyelitis, multiple exost osis, multiple myeloma, and secondary met ast at ic mali gnancy and we recogn ize mul t ipl e inv olvement by exte nding the roen tgen examinat ion to include t he skull, t he long bones, and the chest . Oth er definit e characte rist ics ha ve been est ablished and are expr essed by t he following maxim, which all t hose who di agnose lesions of an y part of the skelet on may well keep in mind: ost eomyelitis sequest rates ; beni gn centra l tumors are enca psulated ; mali gnan t tumors infilt rat e, expa nd, and perfor at e: an d luetic lesions p r esent no characterist ic pi ctur e-syphilis imi tates. 47
B AY S TAT E RoAD
H. Ivy
AND KURT
H.
THOMA
Articles on oral surgery, radiography, and anesthesia should be submitted to Dr. Robert H. Ivy, 1930 Chestnut St., Philadelphia, Pa, Articles on oral pathology should be submitted to Dr. Kurt H. Thoma, 47 Bay State Road, Boston, Mass.
PATHOLOGIC INTERPRETATION OF X-RAY FINDINGS* KURT
H.
THOMA, D.M.D., BOS'l'ON, MASS.
E HAVE arrived at a time in the development of our profession when proper recognition is given to the value of the sciences in the art of practicing dentistry. The reason is quite evident-dental and oral diseases which heretofore were thought to be of purely local origin have been shown to come from metabolic disturbances, blood dyscrasias, and other systemic diseases. In order to treat such conditions successfully one must assume a different attitude from that taken only a few years ago. This especially applies to the science of recognizing disease-diagnosis. Diagnosis today is, in very few dental schools, treated as a separate subject; it is talked about in various courses, but like a fata morgana it is never within practical reach and never taught systematically. It involves a wide knowledge and experience; the diagnostician must be able to interpret laboratory analyses of saliva, blood, and urine, bacteriologic tests, and pathologic roports , he must be able to read roentgen films; and he must have a clear mental picture of the tissue changes brought about by disease-pathology. All methods of examination are important and may be needed before a diagnosis can be made. One alone should not be relied upon, and this applies particularly to the now so popular roentgen examination. Although it is indisputably one of the most valuable means of detecting abnormalities of the teeth and jaws, it should not be regarded as complete and final. Unfortunately, the ordinary roentgenologist makes not even a pretense of studying the symptoms and history of the patient; he only takes x-ray pictures, and from their disclosure he writes a report. Such a report is not a diagnosis, and it is to be regretted that roentgen examination has become a specialty in its own right. It is only an aid, a tool, one of the several tests that should be at the disposal of the diagnostician, but not accessible to the patient, as it is today through commercial x-ray laboratories. Not only must roentgen findings be interpreted on a pathologic basis, but x-ray examination should also have a prominent place in the study of pathology. In the past we have employed the microscope alone in the laboratory, but there is no reason why the roentgen method should not be used as well. The roentgen examination shows the gross involvement of the teeth and jaws best and also the extent to which the pathology has progressed. Generally
W
"Read before the Pennsylvania State and Philadelphia County Dental Societies, February 0. 1936.
383
384
Kurt H. Thorna
it furnishes indications as to the character of the lesion, whether its effect is localized or diffuse, osteolytic or osteoblastic, odontolytie or odontoblastic; whether it is encapsulated, encysted, expanding, infiltrating, or perforating the bone. The x-ray picture therefore does not indicate specific disease but shows the result of the disease, or its effect on the bone and dental structures. The microscopic study, on the other hand, gives a clear picture of the actual tissue changes in disease, demonstrating the nature of the lesion and the systemic reaction caused by it. With the microscope we can visualize what is actually going on, and the greater our power to visualize the pathologic processes the better is our concept of disease. To demonstrate how uncertain and vague the findings by the x-ray method can be, it is only necessary to examine an unusual lesion. This will prove at once that pathologic interpretation is an absolute necessity. Study, for example, the x-ray picture shown in Fig. 1 and ask yourself the question: What is actu-
Fig. l.-Mandibular second molar of a boy ag'ed twelve years. Tooth presented a defective occlusal fissure. Exploration caused hemorrhage. Roentgen examination shows a radiolucent central defect. Pathologic examination is necessary to make a diagnosis.
ally going on in the tooth which shows the central radiolucent area? The answer can be given only by histologic examination. The need for keen pathologic thinking is also demonstrated when using a roentgen picture for the diagnosis of pulp disease. We know that the pulp itself is not visible except for calcareous deposits; therefore secondary evidence must be relied upon to obtain the desired information. An enlargement of the periapical space presents such evidence, as it indicates an inflammatory reaction caused by the infected pulp. The finding of an etiologic factor, such as deep primary or secondary caries, or a parodontal pocket reaching close to the apex, signifies, especially if associated with symptoms, that an infection may have traveled either from the cavity via the pulp to the periapical tissue (descending pulpitis) or from the parodontal pocket to the apex and into the root canal (ascending pulpitis). When bone is involved by disease, the x-ray examination helps first of all to determine whether the effect is of an osteoblastic or osteolytic nature.
Pathologic I nt erp retation of X-ray Findings
385
The osteoblasti c reaction causes new for mation of bone. Thi s may be inside the jaw (enostosis, sclerosis of th e spongiosa, central osteogenic t umor) or outs ide of the jaw (exostosis, torus palatinus and man dibul are, osteogenic tumol's ). In some cases it may be found both inside and outside the bone, as is the case in osteogenic sarcoma. Th e det erm inati on of the actu al pat hologic process, tlie question whet her t he condition is of infectious, tuberc ulous, syphiliti c, or neopla stic na ture, r equires microscopic study . The oste olytic r eact ion causes resorption of bone. The evaluation of the defects caused by this process is mor e difficult sti ll. The lesions may form an are a with an osteitic margin. Thi s means th at there is a gradual chan ge from th e diseased to th e normal without definite demar cat ion. It is characteristi c of infectious resorption, but it may also be caused by an infiltrating tumor (benign giant -cell tumor, carcinoma, and other malignant tumors ). A cystic area has a well-defined, radiopaque margin due to incasement of the lesion by a corti cal
Fig. 2.- Pho t og r a ph of a n . exc ised m a nd ible with s u b maxtll arv g la nds a ttached. of carc in o ma of the lip meta sta s iz in g t o the j a w.
From a case
layer of bone. This condition is seen in all t ypes of odontogenic and fissural cyst s, but may also be encountered in the case of encapsulat ed central tumors (adamantinoma, fibroma ) . Any odontogenic connect ion may favor classification as a follicular or radi cular cyst, while multiple occurrence and trabeculation ind icate neoplastic disease. It must be rememb er ed, however, that f rom all kinds of odonto geni c cysts ada mantinoma or carcinoma may develop wit hout showing th e change in th e roentgen picture at first. Later notching at th e margin or per fora ti on and extension into the neighboring tissue result, and indicat e definite local mali gnancy. 'I'h e so-called punched-out area is left for consideration. It is a well-defined shadow with a definit e mar gin but no cort ical bone sur rounding it. 'When it is seen in dental x-ray pi ctu r es, it is ofte n looked at as a much more ser ious in fect ion than is r epresented by th e indefinite r adiolucent area with osteitic margin . This br in gs out clearl y th e fallacy of r eading x-ra y pictures without a background of pathology. Th e punched-out area means very littl e pathol ogically ; it has to do with t he anatomic involvement of t he bone. It
386
/lu rt 11. T honui
indicates perforation of th e thick, dense, and t herefo re r adi opaque cort ex of t he jaw, and may be caused by denta l in fection as well as t umors, espec ially multiple myeloma which also forms such defects in other bones, especially the r ibs, calvaria, and jaws. All th is t eaches t hat t he x-r ay is a valuable aid to show the presen ce of disease, and that it is useful to disclose th e exte nt of in volvement of th e t eeth and jaws, but t hat it does not give sufficient evidence to make a final diagnosis, Lon g continued comp arative study of jaw lesions by mean s of the x-ray examination and th e microscope is necessary t o in cr ease our diagn osti c knowl edge. This can be accomplished first by sup plying the student with a roentgen film of ever y case he studies wit h t he microscope, and second by examining excised specimens by means of th e x-ray before making th e hist ologic preparations. The value of such a procedu re is app reciat ed when we comp are the photograph of an excised mandible of a case of carcinoma of th e lip ( F ig. 2) with the x-ray of th e specimen showing t he actual involvement of th e bone by metastasis, as seen in Fig. 3.
F ig , 3.- X-r a y p ictur e of t h e s pecime n in Fig. 2 s h owin g osteo lytic d efec t in b od y o f the m and ibl e, d ue t o t h e m etastatic n ew f orm a t io n .
By cont inued comparison with the actual path ologic p rocesses the interp retati on of the various roent gen signs will become more and more accurate. W e have already learned th at t umor s which are either in side or outside the cortex are generall y benign, while those which are both inside and out arc liable to be mali gnant. W e r ecogni ze an indefinit e, so-call ed ost eit ic margin with exte nsions away from th e main defect t o mean spreadin g in t o th e adjacent bone t hroug h infiltrati on. \Ve kn ow that cer tain jaw lesions may be part of a gener alized disease, such as hyperparath yroidi sm, xa nthomatosis, Paget's disease, acromegaly, generalized ost eomyelitis, multiple exost osis, multiple myeloma, and secondary met ast at ic mali gnancy and we recogn ize mul t ipl e inv olvement by exte nding the roen tgen examinat ion to include t he skull, t he long bones, and the chest . Oth er definit e characte rist ics ha ve been est ablished and are expr essed by t he following maxim, which all t hose who di agnose lesions of an y part of the skelet on may well keep in mind: ost eomyelitis sequest rates ; beni gn centra l tumors are enca psulated ; mali gnan t tumors infilt rat e, expa nd, and perfor at e: an d luetic lesions p r esent no characterist ic pi ctur e-syphilis imi tates. 47
B AY S TAT E RoAD